[go: up one dir, main page]
More Web Proxy on the site http://driver.im/
login
Search: a101232 -id:a101232
     Sort: relevance | references | number | modified | created      Format: long | short | data
Smallest prime p such that there is a gap of 2^n between p and the next prime.
+10
6
2, 3, 7, 89, 1831, 5591, 89689, 3851459, 1872851947, 1999066711391, 22790428875364879, 5333419265419188034369535864125349, 55128448018333565337014555712123010955456071077000028555991469751
OFFSET
0,1
COMMENTS
a(11) <= 79419801290172271035479303914142441 and a(12) <= 55128448018333565337014555712123010955456071077000028555991469751. - Abhiram R Devesh, Aug 09 2014
From Zhining Yang, Dec 02 2022: (Start)
a(11) = 5333419265419188034369535864125349, 34 digits, discovered by Helmut Spielauer in 2013
a(12) = 55128448018333565337014555712123010955456071077000028555991469751, 65 digits, discovered by Helmut Spielauer in 2013
a(13) = 192180552346991956641101827551986346298837407139466361414211497406670710665021150917759713696699494356609164354068319457039591759, 129 digits, discovered by Dana Jacobsen in 2016
a(14) = 267552521*631#/210 - 9606, 268 digits, discovered by Dana Jacobsen in 2016
a(15) = 2717*1303#/268590 - 16670, 552 digits, discovered by Dana Jacobsen in 2014
a(16) = 7079*3559#/9870 - 36310, 1517 digits, discovered by Michiel Jansen, Pierre Cami, and Jens Kruse Andersen in 2013
a(17) = 1111111111111111111*9059#/(11#*5237) - 86522, 3899 digits, discovered by Hans Rosenthal in 2017
a(11) to a(17) were searched from Thomas R. Nicely's homepage. (End)
LINKS
C. Hilliard, TwinPrimes Java code.
Thomas R. Nicely, First occurrence prime gaps [For local copy see A000101].
Thomas R. Nicely, Other tables of prime gaps
FORMULA
a(n) = A000230(2^(n-1)). - R. J. Mathar, Jan 12 2007
a(n) = A000230(2^(n-1)) = Min{p|nextprime(p)-p = 2^n} [may need adjusting since offset has been changed].
EXAMPLE
a(2)=7 because 7 and 11 are consecutive primes with difference 2^2=4.
a(3)=89 because 89 and 97 are consecutive primes with difference 2^3=8.
MATHEMATICA
f[n_] := Block[{k = 1}, While[Prime[k + 1] != n + Prime[k], k++ ]; Prime[k]]; Do[ Print[ f[2^n]], {n, 0, 10}] (* Robert G. Wilson v, Jan 13 2005 *)
PROG
(Python)
import sympy
n=0
while n>=0:
....p=2
....while sympy.nextprime(p)-p!=(2**n):
........p=sympy.nextprime(p)
....print(p)
....n=n+1
....p=sympy.nextprime(p)
## Abhiram R Devesh, Aug 09 2014
CROSSREFS
KEYWORD
nonn
AUTHOR
Labos Elemer, Jun 25 2001
EXTENSIONS
a(10) sent by Robert G. Wilson v, Jan 13 2005
STATUS
approved
Smallest prime p such that there is a gap of 6n between p and the next prime.
+10
5
23, 199, 523, 1669, 4297, 9551, 16141, 28229, 35617, 43331, 162143, 31397, 188029, 461717, 404851, 360653, 1444309, 2238823, 492113, 1895359, 1671781, 1357201, 3826019, 11981443, 13626257, 17983717, 39175217, 37305713, 52721113
OFFSET
1,1
FORMULA
a(n) = A000230(3n).
EXAMPLE
d=72 appears after 31397, while smaller d=54,60,66 come later, following primes 35617,43331,162143 respectively.
PROG
(PARI) a(n) = {p=3; q = nextprime(p+1); while((q-p) != 6*n, p = q; q = nextprime(q+1)); p; } \\ Michel Marcus, Mar 12 2016
CROSSREFS
KEYWORD
nonn
AUTHOR
Labos Elemer, Nov 28 2000
EXTENSIONS
Offset corrected by M. F. Hasler, Apr 09 2013
STATUS
approved
First occurrence of prime gap 10*n.
+10
3
139, 887, 4297, 19333, 31907, 43331, 173359, 542603, 404851, 396733, 1468277, 1895359, 5518687, 7621259, 13626257, 33803689, 27915737, 17051707, 142414669, 378043979, 20831323, 47326693, 607010093, 391995431, 387096133, 944192807
OFFSET
1,1
REFERENCES
J.-M. De Koninck, Ces nombres qui nous fascinent, Entry 139, pp 47, Ellipses, Paris 2008.
FORMULA
a(n)=A000230(5n), a(3n) = A224522(n) = A058193(5n). - M. F. Hasler, Apr 09 2013
CROSSREFS
KEYWORD
nonn
AUTHOR
Lekraj Beedassy, Jul 14 2008
EXTENSIONS
Offset corrected by Arkadiusz Wesolowski, Jun 07 2011
STATUS
approved

Search completed in 0.004 seconds