G.f. satisfies: A(x) = exp( Sum_{n>=1} [Sum_{k=0..3*n} T(n,k)^2 * x^k] / A(x)^n * x^n/n ) where T(n,k) equals the coefficient of x^k in (1+x+x^2+x^3)^n.
A248876
G.f. satisfies: A(x) = exp( Sum_{n>=1} [Sum_{k=0..3*n} T(n,k)^2 * x^k] / A(x)^n * x^n/n ) where T(n,k) equals the coefficient of x^k in (1+x+x^2+x^3)^n.
Terms
- a(0) =1a(1) =1a(2) =1a(3) =2a(4) =4a(5) =8a(6) =13a(7) =24a(8) =45a(9) =85a(10) =161a(11) =305a(12) =582a(13) =1116a(14) =2149a(15) =4152a(16) =8049a(17) =15653a(18) =30528a(19) =59695a(20) =117012a(21) =229880a(22) =452565a(23) =892703a(24) =1764099a(25) =3492029a(26) =6923494a(27) =13747483a(28) =27335873a(29) =54427621
External references
- oeis: A248876