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

Author

Paul Curtz, Jan 14 2009

Keywords

• nonn

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).

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]

Extensions

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