A156296 a(1)=1, a(n) = 2 * Sum_{k=1..n-1} (3^k-1)/2 * a(k) for n>=2.
1, 2, 10, 140, 5740, 700280, 255602200, 279628806800, 917462115110800, 9029662136920493600, 266600774592577573540000, 23613897008762965998731960000, 6274708327065504088149055143160000
Offset: 0
Links
- Michael De Vlieger, Table of n, a(n) for n = 0..64
Programs
-
Mathematica
Table[QPochhammer[-1, 3, n+1]/2^(n+1), {n, 0, 15}] (* Vaclav Kotesovec, Mar 24 2017 *)
Formula
a(n) = 2*A015502(n+1) for n>1. - Joe Slater, Mar 23 2017
Extensions
New name from Joerg Arndt, Mar 24 2017