A026021 T(n,[ n/2 ]), where T is the array defined in A026009.

1, 1, 2, 3, 6, 10, 19, 34, 62, 117, 207, 407, 704, 1430, 2431, 5070, 8502, 18122, 30056, 65246, 107236, 236436, 385662, 861764, 1396652, 3157325, 5088865, 11622015, 18642420, 42961470, 68624295, 159419670, 253706790, 593636670, 941630580

Offset: 0

Author

Clark Kimberling

Keywords

• nonn

Crossrefs

Cf. A026009.

Formula

Conjecture: -(n+7)*(5*n-34)*a(n) +8*(-n-14)*a(n-1) +(27*n^2-83*n-428)*a(n-2) +8*(4*n+5)*a(n-3) 44*(n-3)*(7*n-27)*a(n-4)=0. - R. J. Mathar, Jun 20 2013