The On-Line Encyclopedia of Integer Sequences (OEIS)

A068842 revision #2

A068842

Smallest prime larger than 2^n whose digits begin with those of 2^n.

11, 23, 41, 83, 163, 3203, 641, 1283, 25601, 51203, 10243, 20483, 40961, 81929, 163841, 327689, 6553621, 1310723, 2621447, 5242883, 10485767, 20971529, 41943049, 838860817, 167772161, 335544323, 6710886407, 1342177283

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OFFSET

0,1

LINKS

Table of n, a(n) for n=0..27.

EXAMPLE

a(5) = 3203 with leading digits 32 = 2^5.

MATHEMATICA

f[n_] := For[x=10, True, x*=10, For[y=0, y<x, y++, If[PrimeQ[x*n+y], Return[x*n+y]]]]; a[n_] := f[2^n]

CROSSREFS

Cf. A068841.

Sequence in context: A052034 A077041 A190797 * A357364 A199848 A352494

Adjacent sequences: A068839 A068840 A068841 * A068843 A068844 A068845

KEYWORD

nonn,base,new

AUTHOR

Amarnath Murthy (amarnath_murthy(AT)yahoo.com), Mar 10 2002

EXTENSIONS

Edited by Dean Hickerson (dean(AT)math.ucdavis.edu), Jun 09 2002

STATUS

approved