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).
1, 2, 4, 5, 13, 14, 16, 17, 73, 74, 76, 77, 85, 86, 88, 89, 721, 722, 724, 725, 733, 734, 736, 737, 793, 794, 796, 797, 805, 806, 808, 809, 12961, 12962, 12964, 12965, 12973, 12974, 12976, 12977, 13033, 13034, 13036, 13037, 13045, 13046, 13048, 13049
Offset: 1
Keywords
Crossrefs
Cf. A139486.
Programs
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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
Formula
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
Extensions
More terms from Max Alekseyev, Oct 24 2008
Comments