

A321666


Number of arrangements of n 1's, n 2's, ..., n n's avoiding equal consecutive terms and introduced in ascending order.


4



1, 1, 1, 29, 94376, 66218360625, 16985819072511102549, 2421032324142610480402567434373, 271259741131895052775392614041761701799270286, 32119646666355552112999645991677870426882424139287301894021793
(list;
graph;
refs;
listen;
history;
text;
internal format)



OFFSET

0,4


LINKS

Seiichi Manyama, Table of n, a(n) for n = 0..27


FORMULA

a(n) = A321634(n)/n!.
a(n) ~ exp(5/12) * n^((n1)*(2*n1)/2) / (2*Pi)^(n/2).  Vaclav Kotesovec, Nov 24 2018


PROG

(PARI) {a(n) = sum(i=n, n^2, i!*polcoef(sum(j=1, n, (1)^(nj)*binomial(n1, j1)*x^j/j!)^n, i))/n!} \\ Seiichi Manyama, May 27 2019


CROSSREFS

Cf. A190826, A190830, A190833, A190835, A190836, A190837, A278990, A321634.
Sequence in context: A296176 A159437 A185822 * A139775 A303734 A087528
Adjacent sequences: A321663 A321664 A321665 * A321667 A321668 A321669


KEYWORD

nonn


AUTHOR

Seiichi Manyama, Nov 16 2018


STATUS

approved



