A307416 Number of narcissistic group-separable preference profiles.

1, 1, 1, 6, 144, 13440, 4976640, 7390494720, 44033145569280, 1050540969012756480, 100246620373125798297600, 38247242364455762072803737600, 58346834889692144013481754807500800, 355946631376225773365104516210274756198400

Offset

0,4

Links

Table of n, a(n) for n=0..13.

A. Karpov, On the Number of Group-Separable Preference Profiles, Group Decision and Negotiation, 2019, pp. 1-17.

Formula

a(n) = Sum_{k=1..n-1} binomial(n-1, k-1)*2^(2*n*k-2*k^2-n)*a(k)*a(n-k).

Prog

(PARI) a(n) = {j=1; if(n>1, j=sum(k=1, n-1, binomial(n-1, k-1)*2^(2*n*k-2*k^2-n)*a(k)*a(n-k))); j; } \\ Jinyuan Wang, Apr 08 2019

Crossrefs

Sequence in context: A085905 A203978 A090443 * A133460 A166953 A280847

Adjacent sequences: A307413 A307414 A307415 * A307417 A307418 A307419

Keyword

nonn

Author

Alexander Karpov, Apr 07 2019

Extensions

More terms from Jinyuan Wang, Apr 08 2019

Status

approved