A246251 Number of permutations of [n] with exactly six occurrences of the consecutive step pattern up, down, down.

1488257158851, 176902009674966, 13166075391964578, 775944032960346939, 39844140679287441918, 1872063201155821139178, 82897279832156950225548, 3526803545750650310760216, 146090377422354615989531688, 5948505245302032452585146020, 239776137775416266444362226760

Offset

19,1

Links

Alois P. Heinz, Table of n, a(n) for n = 19..160

Formula

a(n) ~ c * (3*sqrt(3)/(2*Pi))^n * n! * n^6, where c = 0.000003054026651631929902... = c0 * (c0-1)^6 / (3^6 * 6!), and c0 = (1 + exp(Pi/sqrt(3))) * sqrt(3) / (2*Pi). - Vaclav Kotesovec, Aug 26 2014

Crossrefs

Column k=6 of A242819.

Sequence in context: A213601 A213646 A288276 * A320943 A248892 A172799

Adjacent sequences: A246248 A246249 A246250 * A246252 A246253 A246254

Keyword

nonn

Author

Alois P. Heinz, Aug 20 2014

Status

approved