a(n) = binomial(2^n + 3*n + 1, n).A132689a(n) = binomial(2^n + 3*n + 1, n).Terms a(0) =1a(1) =6a(2) =55a(3) =816a(4) =23751a(5) =1712304a(6) =377447148a(7) =294109729200External referencesoeis: A132689