A160230 a(n) = A004760(n+1)-A160217(n), n>=1.

0, 0, 0, 3, 2, 0, 0, 6, 6, 4, 4, 3, 2, 0, 0, 15, 14, 12, 12, 11, 10, 8, 8, 6, 6, 4, 4, 3, 2, 0, 0, 30, 30, 28, 28, 27, 26, 24, 24, 22, 22, 20, 20, 19, 18, 16, 16, 15, 14, 12, 12, 11, 10, 8, 8, 6, 6, 4, 4, 3, 2, 0, 0, 63, 62, 60, 60, 59, 58, 56, 56, 54, 54, 52, 52, 51, 50

Offset: 1

Author

Vladimir Shevelev, May 04 2009

Keywords

• nonn

Examples

			a(2)=2a(1)=0; a(3)=2a(1)=0; a(4)=2a(2)+3=3; a(5)=2a(2)+2=2.
		

Crossrefs

Cf. A004760, A160217, A007814.

Programs

PARI

is0(n)= (n<2) || binary(n)[2]; \\ A004760
list0(nn) = select(x->is0(x), vector(nn, k, k));
list7(nn) = {my(va = vector(nn)); va[1] = 3; for (n=2, nn, va[n]= nexta(va[n-1], n);); va;} \\ A160217
listd(nn) = {my(v7 = list7(nn), v0 = list0(nn)); vector(min(#v0-1, #v7), k, v0[k+1] - v7[k]);} \\ Michel Marcus, Dec 15 2018

Formula

a(1)=0; a(2n)=a(2n+1)=2a(n) if A007814(n) is even, a(2n)=a(2n+1)+1=2a(n)+3 if A007814(n) is odd.

Extensions

Edited by N. J. A. Sloane, May 08 2009

More terms from Michel Marcus, Dec 15 2018