cp's OEIS Frontend

A139485 a(1)=1. For m >= 0 and 1 <= k <= 2^m, a(2^m +k) = a(k) + Sum_{j=1..2^m} a(j).

%I A139485 #13 Feb 20 2018 07:27:45
%S A139485 1,2,4,5,13,14,16,17,73,74,76,77,85,86,88,89,721,722,724,725,733,734,
%T A139485 736,737,793,794,796,797,805,806,808,809,12961,12962,12964,12965,
%U A139485 12973,12974,12976,12977,13033,13034,13036,13037,13045,13046,13048,13049
%N A139485 a(1)=1. For m >= 0 and 1 <= k <= 2^m, a(2^m +k) = a(k) + Sum_{j=1..2^m} a(j).
%C A139485 A139486(n) = Sum_{j=1..2^n} a(j).
%F A139485 For odd n, a(n) = Sum_{j=0..k} b(j) * A139486(j), where n = Sum_{j=0..k} b(j) * 2^j is the binary representation of n. For even n, a(n) = a(n-1) + 1. - _Max Alekseyev_, Oct 24 2008
%o A139485 (PARI) { A139485(n) = local(b); if(n%2==0,return(a(n-1)+1)); b=Vecrev(binary(n)); sum(j=1,#b,b[j]*prod(i=0,j-2,2^i+2)) } \\ _Max Alekseyev_, Oct 24 2008
%Y A139485 Cf. A139486.
%K A139485 nonn
%O A139485 1,2
%A A139485 _Leroy Quet_, Apr 23 2008
%E A139485 More terms from _Max Alekseyev_, Oct 24 2008