A171252 Least power of 2 to have at least n consecutive digits 'n' in its decimal expansion.

0, 0, 43, 83, 192, 973, 2269, 972, 25263, 42485

Offset: 0

Author

M. F. Hasler, Dec 06 2009

Keywords

• base
• fini
• full
• nonn

Comments

As it stands, the definition makes only sense for (decimal digits) n=0,...,9. Replacing "decimal" by, e.g., base-(prime(n)), the sequence could be defined for all n. (However, e.g., base-(n+1) would not work, since in base 4 no power of 2 has a digit "3".)

Crossrefs

Cf. A131535 - A131543.

Programs

PARI

A171252(n)={my(p=10^n, t); n*=p\9; for(k=0,1e9, t=2^k; until( n>t\=10, t%p==n & return(k)))}
for(d=0,9, print(d" "A171252(d)))