A275540 a(n) = n! + n!! - n - 1.

1, 0, 1, 5, 27, 129, 761, 5137, 40695, 363815, 3632629, 39927183, 479047667, 6227155921, 87178936305, 1307676395009, 20922800209903, 355687462555407, 6402373891522541, 121645101063561055, 2432902011892531179

Offset

0,4

Links

Table of n, a(n) for n=0..20.

Mathematica

Table[n! + n!! - n - 1, {n, 0, 20}] (* Bruno Berselli, Aug 11 2016 *)

Crossrefs

Cf. A006882, A110903, A128882.

Sequence in context: A069993 A249995 A009027 * A037498 A198771 A084177

Adjacent sequences: A275537 A275538 A275539 * A275541 A275542 A275543

Keyword

nonn,easy

Author

Olivier Gérard, Aug 01 2016

Status

approved