A275929 a(n) = 2*(n-1)! + n + 1.

4, 5, 8, 17, 54, 247, 1448, 10089, 80650, 725771, 7257612, 79833613, 958003214, 12454041615, 174356582416, 2615348736017, 41845579776018, 711374856192019, 12804747411456020, 243290200817664021, 4865804016353280022, 102181884343418880023, 2248001455555215360024

Offset: 1

Author

N. J. A. Sloane, Aug 30 2016

Keywords

• nonn

Links

• Vincenzo Librandi, Table of n, a(n) for n = 1..200
• R. C. Castillo, On the Sum of Corresponding Factorials and Triangular Numbers: Runsums, Trapezoids and Politeness, Asia Pacific Journal of Multidisciplinary Research, 3 (2015), 95-101.

Programs

Magma

[2*Factorial(n-1) + n + 1: n in [1..30]]; // Vincenzo Librandi, Aug 31 2016

Maple

seq(2*(n-1)! + n + 1,n=1..30); # Robert Israel, Aug 30 2016

Mathematica

Table[2 (n - 1)! + n + 1, {n, 23}] (* Michael De Vlieger, Aug 30 2016 *)

Formula

E.g.f.: (1+x)*exp(x) - 2*log(1-x) - 1. - Robert Israel, Aug 30 2016