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Number of isoscent sequences of length n with exactly seven ascents.
2

%I #4 Jun 01 2014 18:44:51

%S 436,45146,1830826,45369299,826196076,12168531813,153430719591,

%T 1718168937922,17525279293159,165802561604726,1474718822704304,

%U 12459599973722036,100805357136035992,786035745070774366,5938016635175121413,43645066989439738813,313228673357655892678

%N Number of isoscent sequences of length n with exactly seven ascents.

%H Joerg Arndt and Alois P. Heinz, <a href="/A243233/b243233.txt">Table of n, a(n) for n = 12..100</a>

%p b:= proc(n, i, t) option remember; `if`(n<1, 1, expand(add(

%p `if`(j>i, x, 1) *b(n-1, j, t+`if`(j=i, 1, 0)), j=0..t+1)))

%p end:

%p a:= n-> coeff(b(n-1, 0$2), x, 7):

%p seq(a(n), n=12..35);

%Y Column k=7 of A242351.

%K nonn

%O 12,1

%A _Joerg Arndt_ and _Alois P. Heinz_, Jun 01 2014