A062525 8^a(n) is smallest power of 8 containing the string 'n'.

4, 0, 3, 5, 2, 3, 2, 5, 1, 4, 10, 14, 3, 9, 6, 7, 8, 9, 10, 12, 7, 6, 17, 21, 10, 17, 6, 5, 9, 20, 26, 25, 5, 21, 9, 15, 12, 10, 13, 14, 4, 10, 9, 14, 6, 11, 14, 12, 17, 13, 18, 3, 7, 29, 13, 13, 16, 25, 11, 11, 20, 25, 6, 27, 2, 14, 24, 8, 5, 20, 23, 7, 8, 10, 10, 13

Offset: 0

Author

Robert G. Wilson v, Jun 24 2001

Keywords

• base
• nonn

Links

• Robert Israel, Table of n, a(n) for n = 0..9999

Crossrefs

Cf. A030000, A063571, A176768.

Programs

Maple

F:= proc(dmax) local R,count,x,N,L,d,i,v, p;
count:= 0: x:= 1/8: N:= 10^dmax:
for p from 0 while count < N do
  x:= 8*x;
  L:= convert(x,base,10);
  for d from 1 to min(dmax, nops(L)) do
    for i from 1 to nops(L)-d+1 do
      v:= add(L[j]*10^(j-i),j=i..i+d-1);
      if not assigned(R[v]) then count:= count+1; R[v]:= p fi
od od od;
seq(R[v],v=0..N-1);
end proc:
F(2); # Robert Israel, Dec 25 2019

Mathematica

Table[k = 0; While[ StringPosition[ ToString[8^k], ToString[n] ] == {}, k++ ]; k, {n, 0, 75} ]
Join[{4,0},With[{c=Table[{n,IntegerDigits[8^n]},{n,50}]},Table[ SelectFirst[ c,SequenceCount[ #[[2]],IntegerDigits[k]]>0&],{k,2,80}]][[All,1]]] (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, Apr 13 2019 *)