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A044277 Numbers n such that string 2,8 occurs in the base 9 representation of n but not of n-1. 1
26, 107, 188, 234, 269, 350, 431, 512, 593, 674, 755, 836, 917, 963, 998, 1079, 1160, 1241, 1322, 1403, 1484, 1565, 1646, 1692, 1727, 1808, 1889, 1970, 2051, 2106, 2213, 2294, 2375, 2421, 2456, 2537, 2618, 2699, 2780, 2861 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Robert Israel, Table of n, a(n) for n = 1..10000

MAPLE

N:= 6000: # to get all terms <= N

f:= proc(n) local L, Q;

  L:= convert(n, base, 9);

  Q:= map(`+`, [ListTools:-SearchAll(8, L[1..-2])], 1);

  if ormap(t -> (L[t]=2), Q) then 1 else 0 fi;

end proc:

V:= Vector(N, f):

W:= V[2..-1] - V[1..-2]:

select(t -> (W[t-1]=1), [$2..N]); # Robert Israel, Feb 24 2017

PROG

(PARI) has(n)=while(n>25, if(n%81==26, return(1)); n\=9); 0

is(n)=has(n) && !has(n-1) \\ Charles R Greathouse IV, Feb 24 2017

CROSSREFS

Sequence in context: A042320 A042322 A042324 * A044658 A024381 A262756

Adjacent sequences:  A044274 A044275 A044276 * A044278 A044279 A044280

KEYWORD

nonn,base

AUTHOR

Clark Kimberling

STATUS

approved

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Last modified January 23 21:55 EST 2021. Contains 340386 sequences. (Running on oeis4.)