A026153 T(n,n-2), where T is the array in A026148.

1, 2, 7, 20, 60, 176, 517, 1512, 4415, 12870, 37477, 109044, 317109, 921870, 2679510, 7787904, 22636503, 65804638, 191332945, 556456060, 1618813834, 4710869108, 13713658368, 39935698400, 116340344575, 339050396646, 988474306017

Offset

2,2

Links

Table of n, a(n) for n=2..28.

Formula

Conjecture: -(n+8)*(n-118)*a(n) +(-n^2-561*n-2878)*a(n-1) +2*(38*n^2+203*n-1070)*a(n-2) +2*(-116*n^2+781*n+2493)*a(n-3) +(13*n^2-1012*n+3888)*a(n-4) +3*(107*n-423)*(n-4)*a(n-5)=0. - R. J. Mathar, Jun 23 2013

Crossrefs

First differences of A026327.

Sequence in context: A007460 A034899 A026124 * A025180 A201967 A116950

Adjacent sequences: A026150 A026151 A026152 * A026154 A026155 A026156

Keyword

nonn

Author

Clark Kimberling

Status

approved