a(n) = 2^floor(n/2) n! [x^n] exp(x+x^2/4), where [x^n] f(x) denotes the coefficient of x^n in the expansion of f(x).

A242818

a(n) = 2^floor(n/2) n! [x^n] exp(x+x^2/4), where [x^n] f(x) denotes the coefficient of x^n in the expansion of f(x).

Terms

    a(0) =1a(1) =1a(2) =3a(3) =5a(4) =19a(5) =39a(6) =173a(7) =407a(8) =2025a(9) =5281a(10) =28787a(11) =81597a(12) =479851a(13) =1459015a(14) =9156093a(15) =29582303a(16) =196506001a(17) =669822849a(18) =4680247715a(19) =16737058997a(20) =122398824579a(21) =457140004519

External references