A078155 A078152(n!).

0, 0, 0, 0, 4, 22, 80, 304, 1043, 3538, 12094, 42979, 156237, 587926, 2283038, 9142910, 37708601, 160014979, 697523776, 3119511496, 14295524835, 67052144163, 321571055089, 1575370699764, 7876854373196, 40164235356266, 208699490940770

Offset: 1

Author

Labos Elemer, Nov 27 2002

Keywords

• nonn

Links

• Michael De Vlieger, Table of n, a(n) for n = 1..807

Crossrefs

Cf. A078152, A078153, A078154, A078156, A078157, A078158.

Programs

Mathematica

Table[ Length[ Union[ Table[ Floor[w!/j], {j, 1, w!}]]] - DivisorSigma[0, w! ], {w, 1, 11}]
(* Second program: *)
Array[Floor@ Sqrt[4 # + 1] - 1 - DivisorSigma[0, #] &[#!] &, 27] (* Michael De Vlieger, Dec 13 2018 *)

Formula

a(n) = A078152(n!) = A055086(n!) - A000005(n!).

Extensions

Extended by Robert G. Wilson v, Dec 02 2002

a(11) corrected and terms a(12) onward added by Max Alekseyev, Feb 12 2012