A173316 a(n) = 6*n! - 1.

5, 5, 11, 35, 143, 719, 4319, 30239, 241919, 2177279, 21772799, 239500799, 2874009599, 37362124799, 523069747199, 7846046207999, 125536739327999, 2134124568575999, 38414242234367999, 729870602452991999, 14597412049059839999, 306545653030256639999

Offset: 0

Author

Vincenzo Librandi, Feb 16 2010

Keywords

• nonn
• easy

Links

• Vincenzo Librandi, Table of n, a(n) for n = 0..200

Crossrefs

Cf. sequences of the type k*n!-1: A033312 (k=1), A020543 (k=2), A173323 (k=3), A173321 (k=4), A173317 (k=5).

Programs

Magma

[6*Factorial(n)-1: n in [0..25]]; // Vincenzo Librandi, Sep 30 2013

Magma

[5] cat [n eq 1 select n+4 else n*Self(n-1)+n-1: n in [1..25] ]; // Vincenzo Librandi, Sep 30 2013

Mathematica

Table[6 n! - 1, {n, 0, 25}] (* Vincenzo Librandi, Sep 30 2013 *)

Formula

a(0)=5, a(n) = n*a(n-1)+n-1. - Vincenzo Librandi, Sep 30 2013