A139175 a(n) = (n! - 5)/5.

23, 143, 1007, 8063, 72575, 725759, 7983359, 95800319, 1245404159, 17435658239, 261534873599, 4184557977599, 71137485619199, 1280474741145599, 24329020081766399, 486580401635327999

Offset: 5

Author

Artur Jasinski, Apr 11 2008

Keywords

• nonn

Comments

Original name: Natural numbers of the form (n!-5)/5.

Links

• Vincenzo Librandi, Table of n, a(n) for n = 5..300

Crossrefs

Cf. A033312, A139172, A139173, A139174, A139175, A139176, A139177, A139183, A139184.

Programs

Magma

[(Factorial(n)-5)/5: n in [5..25]]; // Vincenzo Librandi, Jul 20 2011

Mathematica

Table[(n! - 5)/5, {n, 5, 20}]

PARI

for(n=5,25, print1((n! -5)/5, ", ")) \\ G. C. Greubel, Oct 18 2018

Formula

E.g.f.: (120 - 60*x^2 - 40*x^3 - 15*x^4 + 19*x^5)/(120*(1-x)) - exp(x). - G. C. Greubel, Oct 18 2018

Extensions

Corrected offset from 4 to 5 by Vincenzo Librandi, Jul 20 2011

New name from Jon E. Schoenfield, Oct 18 2018