A151785 a(n) = 7^(wt(n) - 1) where wt(n) is the binary weight of n (A000120).

1, 1, 7, 1, 7, 7, 49, 1, 7, 7, 49, 7, 49, 49, 343, 1, 7, 7, 49, 7, 49, 49, 343, 7, 49, 49, 343, 49, 343, 343, 2401, 1, 7, 7, 49, 7, 49, 49, 343, 7, 49, 49, 343, 49, 343, 343, 2401, 7, 49, 49, 343, 49, 343, 343, 2401, 49, 343, 343, 2401, 343, 2401, 2401, 16807, 1, 7, 7, 49, 7, 49

Offset: 1

Author

N. J. A. Sloane, Jun 25 2009

Keywords

• nonn

Links

• Amiram Eldar, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A000120, A000420.

Programs

Mathematica

7^(DigitCount[Range[70],2,1]-1) (* Harvey P. Dale, Feb 15 2015 *)