A171252 - OEIS

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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

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OFFSET

0,3

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".)

LINKS

Table of n, a(n) for n=0..9.

PROG

(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)))

CROSSREFS

Cf. A131535 - A131543.

Sequence in context: A289730 A045238 A139982 * A119487 A180549 A247436

Adjacent sequences: A171249 A171250 A171251 * A171253 A171254 A171255

KEYWORD

base,fini,full,nonn

AUTHOR

M. F. Hasler, Dec 06 2009

STATUS

approved