The On-Line Encyclopedia of Integer Sequences (OEIS)

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A104420

Numbers n such that n, p[n], p[n]+n, p[n]-n and p[n]*n all are 9-less.
(history; published version)

#7 by Harvey P. Dale at Mon Oct 14 14:22:16 EDT 2019

STATUS

editing

approved

#6 by Harvey P. Dale at Mon Oct 14 14:22:13 EDT 2019

LINKS

Harvey P. Dale, <a href="/A104420/b104420.txt">Table of n, a(n) for n = 1..1000</a>

STATUS

approved

editing

#5 by Harvey P. Dale at Mon Oct 14 14:20:53 EDT 2019

STATUS

editing

approved

#4 by Harvey P. Dale at Mon Oct 14 14:20:50 EDT 2019

MATHEMATICA

nlsQ[n_]:=Module[{p=Prime[n]}, Max[DigitCount[{n, p, p+n, p-n, p*n}, 10, 9]] == 0]; Select[Range[300], nlsQ] (* Harvey P. Dale, Oct 14 2019 *)

STATUS

approved

editing

#3 by Russ Cox at Fri Mar 30 17:26:11 EDT 2012

AUTHOR

_Zak Seidov (zakseidov(AT)yahoo.com), _, Mar 07 2005

Discussion

Fri Mar 30

17:26

OEIS Server: https://oeis.org/edit/global/139

#2 by N. J. A. Sloane at Fri Feb 24 03:00:00 EST 2006

MATHEMATICA

id[x_]:=IntegerDigits[x]; pr[i_]:=Prime[i]; ra=Range[300]; A104420=Select[ra, Last[Union[id[ # ], id[pr[ # ]], id[pr[ # ]+# ], id[pr[ # ]-# ], id[pr[ # ]*# ]]]!=9&]

KEYWORD

nonn,base,new

#1 by N. J. A. Sloane at Sat Apr 09 03:00:00 EDT 2005

NAME

Numbers n such that n, p[n], p[n]+n, p[n]-n and p[n]*n all are 9-less.

DATA

1, 2, 3, 4, 5, 11, 13, 15, 26, 27, 33, 36, 48, 51, 55, 60, 61, 65, 71, 83, 100, 101, 106, 112, 115, 116, 117, 123, 126, 151, 170, 173, 177, 200, 203, 206, 216, 221, 225, 230, 231, 233, 234, 235, 240, 241, 253, 255, 271, 275, 281, 283, 284, 286, 287

OFFSET

1,2

COMMENTS

n, p[n], p[n]+n, p[n]-n and p[n]*n all are 0-less gives A104419.

MATHEMATICA

id[x_]:=IntegerDigits[x]; pr[i_]:=Prime[i]; ra=Range[300]; A104420=Select[ra, Last[Union[id[ # ], id[pr[ # ]], id[pr[ # ]+# ], id[pr[ # ]-# ], id[pr[ # ]*# ]]]!=9&]

CROSSREFS

Cf. A104419.

KEYWORD

nonn,base

AUTHOR

Zak Seidov (zakseidov(AT)yahoo.com), Mar 07 2005

STATUS

approved