A031147 Smallest power of 2 containing exactly n zeros.

1, 1024, 4398046511104, 8796093022208, 604462909807314587353088, 309485009821345068724781056, 1267650600228229401496703205376, 5070602400912917605986812821504, 784637716923335095479473677900958302012794430558004314112

Offset: 0

Author

N. J. A. Sloane

Keywords

• nonn
• easy
• base

Crossrefs

Cf. A031146.

Programs

Mathematica

Table[SelectFirst[{#,DigitCount[#,10,0]}&/@(2^Range[0,2000]),#[[2]]==n&],{n,0,8}][[;;,1]] (* Harvey P. Dale, Sep 10 2024 *)

PARI

A031147(n)=for(k=n, oo, #select(d->!d, digits(2^k))==n&&return(2^k)) \\ M. F. Hasler, Jun 15 2018

Formula

a(n) = 2^A031146(n). - M. F. Hasler, Jun 15 2018 (corrected by Sean A. Irvine, Apr 11 2020)

Extensions

More terms from Erich Friedman

a(8) added by M. F. Hasler, Jun 16 2018