A182437 a(0)=0, a(n) = (a(n-1) XOR n) * (n+1).

0, 2, 0, 12, 40, 270, 1848, 14840, 133488, 1334970, 14684560, 176214852, 2290793128, 32071103750, 481066556280, 7697064900464, 130850103307616, 2355301859537394, 44750735331210144, 895014706624203260, 18795308839108268040, 413496794460381897342

Offset: 0

Author

Alex Ratushnyak, Apr 28 2012

Keywords

• nonn
• base

Comments

for n<12, a(n)=A180189(n).

Crossrefs

Cf. A182420, A180189.

Programs

Mathematica

nxt[{n_,a_}]:={n+1,BitXor[a,n+1](n+2)}; NestList[nxt,{0,0},30][[All,2]] (* Harvey P. Dale, Nov 01 2017 *)

Python

a=0
for i in range(1,55):
  print(a, end=', ')
  a ^= i
  a *= i+1

Formula

a(0)=0, for n>0, a(n) = (a(n-1) XOR n) * (n+1).