A249435 a(1) = 0, after which one less than prime powers p^m with exponent m >= 2.

0, 3, 7, 8, 15, 24, 26, 31, 48, 63, 80, 120, 124, 127, 168, 242, 255, 288, 342, 360, 511, 528, 624, 728, 840, 960, 1023, 1330, 1368, 1680, 1848, 2047, 2186, 2196, 2208, 2400, 2808, 3124, 3480, 3720, 4095, 4488, 4912, 5040, 5328, 6240, 6560, 6858, 6888, 7920, 8191, 9408, 10200, 10608, 11448

Offset: 1

Author

Antti Karttunen, Nov 02 2014

Keywords

• nonn

Links

• Charles R Greathouse IV, Table of n, a(n) for n = 1..10000

Crossrefs

One less than A025475.

Subsequence of A181062 and also a subsequence of A249433 (after the initial zero).

Union of sequences A000225, A024023, A024049, A024075, A024127, etc. without their term a(1).

Apart from the first term, subsequence of A045542.

Programs

PARI

list(lim)=my(v=List([0])); lim=lim\1+1; for(m=2,logint(lim,2), forprime(p=2,sqrtnint(lim,m), listput(v, p^m-1))); Set(v) \\ Charles R Greathouse IV, Aug 26 2015

Scheme

(define (A249435 n) (- (A025475 n) 1))

Formula

a(n) = A025475(n) - 1.