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 A171185 G.f.: exp( Sum_{n>=1} (x^n/n)*[Sum_{k=0..[n/2]} A034807(n,k)^3] ), where A034807 is a triangle of Lucas polynomials. 1
 1, 1, 5, 14, 40, 126, 408, 1332, 4473, 15377, 53627, 189724, 680475, 2467975, 9038578, 33399571, 124400702, 466619283, 1761467038, 6688059913, 25527326897, 97901917060, 377123873505, 1458573962761, 5662223702216, 22056563938599 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,3 LINKS EXAMPLE G.f.: A(x) = 1 + x + 5*x^2 + 14*x^3 + 40*x^4 + 126*x^5 + 408*x^6 +... log(A(x)) = x + 9*x^2/2 + 28*x^3/3 + 73*x^4/4 + 251*x^5/5 + 954*x^6/6 +...+ A171215(n)*x^n/n +... PROG (PARI) {a(n)=polcoeff(exp(sum(m=1, n, (x^m/m)*sum(k=0, m\2, (binomial(m-k, k)+binomial(m-k-1, k-1))^3))+x*O(x^n)), n)} CROSSREFS Cf. A171215, A093128, A171186. Sequence in context: A023871 A274598 A327682 * A122485 A198086 A272018 Adjacent sequences:  A171182 A171183 A171184 * A171186 A171187 A171188 KEYWORD nonn AUTHOR Paul D. Hanna, Dec 14 2009 STATUS approved

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Last modified November 26 17:11 EST 2020. Contains 338641 sequences. (Running on oeis4.)