A154699 Terms in A014217 pairwise swapped.

1, 1, 4, 2, 11, 6, 29, 17, 76, 46, 199, 122, 521, 321, 1364, 842, 3571, 2206, 9349, 5777, 24476, 15126, 64079, 39602, 167761, 103681, 439204, 271442, 1149851, 710646, 3010349, 1860497, 7881196, 4870846, 20633239, 12752042

Offset

0,3

Comments

We can build an auxiliary b(n)=a(n+1)-2a(n) = -1,2,-6,7,..., its bisection b(2n)=a(2n+2)-2a(2n), then take the first differences b(2n+2)-b(2n) = a(2n+4)-3*a(2n+2)+2*a(2n) = -5, -10, -25, -65 and have obtained -A106729(n).

Links

Table of n, a(n) for n=0..35.

Formula

a(2n)=A014217(2n+1). a(2n+1)=A014217(2n).

a(n)=4*a(n-2)-4*(n-4)+a(n-6). G.f.: (1+x-2x^3-x^4+2x^5)/((1-x)(1+x)(x^2+x-1)(x^2-x-1)). [R. J. Mathar, Jan 23 2009]

Crossrefs

Sequence in context: A191434 A163918 A318784 * A213568 A185878 A182870

Adjacent sequences: A154696 A154697 A154698 * A154700 A154701 A154702

Keyword

nonn

Author

Paul Curtz, Jan 14 2009

Extensions

Edited and extended by R. J. Mathar, Jan 23 2009

Status

approved