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a(1) = 0, after which one less than prime powers p^m with exponent m >= 2.
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%I #11 Aug 26 2015 12:57:29

%S 0,3,7,8,15,24,26,31,48,63,80,120,124,127,168,242,255,288,342,360,511,

%T 528,624,728,840,960,1023,1330,1368,1680,1848,2047,2186,2196,2208,

%U 2400,2808,3124,3480,3720,4095,4488,4912,5040,5328,6240,6560,6858,6888,7920,8191,9408,10200,10608,11448

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

%H Charles R Greathouse IV, <a href="/A249435/b249435.txt">Table of n, a(n) for n = 1..10000</a>

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

%o (Scheme) (define (A249435 n) (- (A025475 n) 1))

%o (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

%Y One less than A025475.

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

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

%Y Apart from the first term, subsequence of A045542.

%K nonn

%O 1,2

%A _Antti Karttunen_, Nov 02 2014