A111686 (n+1) + (n+1)(n+2) + ..., with n terms.
2, 15, 144, 1925, 33648, 726327, 18636560, 553680369, 18684924840, 705833193923, 29502690532392, 1351724235304365, 67359683340291104, 3627011494019437935, 209846445862386234528, 12982402818188717219657, 855210841645834409812920
Offset: 1
Keywords
Examples
a(3) = 4+ 4*5 +4*5*6 = 144.
Links
- Robert Israel, Table of n, a(n) for n = 1..365
- Eric Weisstein's World of Mathematics, Rising Factorial.
Programs
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Maple
a:=n->sum((n+j)!,j=1..n)/n!: seq(a(n),n=1..18); # Emeric Deutsch, Aug 27 2005
Extensions
a(6)-a(10) from Jonathan Vos Post Aug 17 2005
More terms from Emeric Deutsch, Aug 27 2005