OFFSET
1,3
LINKS
Alois P. Heinz, Table of n, a(n) for n = 1..448
Aubrey Blecher, Charlotte Brennan, Arnold Knopfmacher, Toufik Mansour, and Mark Shattuck, Pushes in permutations, J. Comb. Math. Comb. Comp. (2020) Vol. 115, 77-95.
FORMULA
a(n) = Sum_{k=0..n-1} k*k!*((k+1)^(n-k)-k^(n-k)).
a(n) = Sum_{k=0..n*(n-1)/2} k*A127452(n-1,k). - Paul D. Hanna, Jan 15 2007
a(n) = Sum_{k=0..n-1} k * A180190(n,k). - Alois P. Heinz, Feb 21 2019
MATHEMATICA
Table[Sum[k*k!*((k+1)^(n-k)-k^(n-k)), {k, 0, n-1}], {n, 1, 20}] (* Vaclav Kotesovec, Mar 17 2014 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
STATUS
approved