Coefficient of x^2 in the reduction of the polynomial (x+2)^n by x^3->x^2+x+1.

A192803

Coefficient of x^2 in the reduction of the polynomial (x+2)^n by x^3->x^2+x+1.

Terms

    a(0) =0a(1) =0a(2) =1a(3) =7a(4) =34a(5) =144a(6) =575a(7) =2239a(8) =8632a(9) =33164a(10) =127297a(11) =488571a(12) =1875346a(13) =7199124a(14) =27637959a(15) =106107659a(16) =407374592a(17) =1564024808a(18) =6004739025a(19) =23053921567a(20) =88510638482a(21) =339817775144

External references