A182251 a(0) = 0, a(n) = (a(n-1) OR n) * n.

0, 1, 6, 21, 84, 425, 2586, 18137, 145096, 1305873, 13058830, 143647141, 1723765788, 22408955257, 313725373682, 4705880605425, 75294089686800, 1279999524675617, 23039991444161430, 437759837439067189, 8755196748781343780, 183859131724408219737, 4044900897936980834346

Offset: 0

Author

Alex Ratushnyak, Apr 20 2012

Keywords

• base
• nonn

Links

• Harvey P. Dale, Table of n, a(n) for n = 0..449

Crossrefs

Cf. A080098.

Programs

Mathematica

a[0]=0; a[n_]:=n BitOr[a[n-1],n]; Array[a,23,0] (* Stefano Spezia, Apr 15 2022 *)
nxt[{n_,a_}]:={n+1,BitOr[a,n+1](n+1)}; NestList[nxt,{0,0},30][[All,2]] (* Harvey P. Dale, Feb 08 2023 *)

PARI

a(n) = if (n==0, 0, n*bitor(a(n-1), n)); \\ Michel Marcus, Apr 16 2022

Python

a=0
for i in range(1,51):
  print(a)
  a |= i
  a *= i

Formula

a(0) = 0, a(n) = (a(n-1) OR n) * n, where OR is the bitwise logical inclusive-OR operator.