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A078155
A078152(n!).
5
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
1,5
LINKS
FORMULA
a(n) = A078152(n!) = A055086(n!) - A000005(n!).
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 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Labos Elemer, Nov 27 2002
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
STATUS
approved