A044277 Numbers n such that string 2,8 occurs in the base 9 representation of n but not of n-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

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