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A176768
Smallest power of 8 whose decimal expansion contains n.
2
4096, 1, 512, 32768, 64, 512, 64, 32768, 8, 4096, 1073741824, 4398046511104, 512, 134217728, 262144, 2097152, 16777216, 134217728, 1073741824, 68719476736, 2097152, 262144, 2251799813685248, 9223372036854775808, 1073741824
OFFSET
0,1
COMMENTS
This is to 8 as A176763 is to 3 and as A030001 is to 2.
LINKS
FORMULA
a(n) = MIN{A001018(i) such that n in decimal representation is a substring of A001018(i)}.
a(n) = 8^A062525(n). - Michel Marcus, Sep 30 2014
EXAMPLE
a(1) = 1 because 8^0 = 1 has "1" as a substring (not a proper substring, though).
a(2) = 512 because 8^3 = 512 has "2" as a substring.
a(3) = 32768 because 8^5 = 32768 has "3" as a substring.
MAPLE
F:= proc(dmax) local R, count, x, N, L, d, i, v;
count:= 0: x:= 1/8: N:= 10^dmax:
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]:= x fi
od od od:
seq(R[v], v=0..N-1);
end proc:
F(2); # Robert Israel, Dec 25 2019
MATHEMATICA
A176768[n_] := Block[{k = -1}, While[StringFreeQ[IntegerString[8^++k], IntegerString[n]]]; 8^k]; Array[A176768, 50, 0] (* Paolo Xausa, Apr 04 2024 *)
CROSSREFS
KEYWORD
base,easy,nonn
AUTHOR
Jonathan Vos Post, Apr 25 2010
EXTENSIONS
More terms from Sean A. Irvine and Jon E. Schoenfield, May 05 2010
a(0)=4096 inserted by Robert Israel, Dec 25 2019
STATUS
approved