G.f. is the polynomial (1-x^3) * (1-x^6) * (1-x^9) * (1-x^12) * (1-x^15) * (1-x^18) * (1-x^21) * (1-x^24) * (1-x^27) * (1-x^30) * (1-x^33) * (1-x^36) * (1-x^39) / (1-x)^13.
A162631
G.f. is the polynomial (1-x^3) * (1-x^6) * (1-x^9) * (1-x^12) * (1-x^15) * (1-x^18) * (1-x^21) * (1-x^24) * (1-x^27) * (1-x^30) * (1-x^33) * (1-x^36) * (1-x^39) / (1-x)^13.
Terms
- a(0) =1a(1) =13a(2) =91a(3) =454a(4) =1807a(5) =6097a(6) =18108a(7) =48555a(8) =119691a(9) =274911a(10) =594438a(11) =1219920a(12) =2391662a(13) =4503266a(14) =8179652a(15) =14385775a(16) =24574822a(17) =40886248a(18) =66405664a(19) =105500290a(20) =164245393a(21) =250958800a(22) =376862161a(23) =556889086a(24) =810661540a(25) =1163656897
External references
- oeis: A162631