A160505 a(1)=1, a(n) = p*a(n-1), where p is the smallest prime satisfying gcd(n,p)=1.

1, 3, 6, 18, 36, 180, 360, 1080, 2160, 6480, 12960, 64800, 129600, 388800, 777600, 2332800, 4665600, 23328000, 46656000, 139968000, 279936000, 839808000, 1679616000, 8398080000, 16796160000, 50388480000, 100776960000

Offset

1,2

Links

Harvey P. Dale, Table of n, a(n) for n = 1..1000

Maple

A053669 := proc(n) local i, p ; for i from 1 do p := ithprime(i) ; if igcd(n, p) = 1 then return p; end if; end do: end proc:
A160505 := proc(n) option remember; if n = 1 then 1; else procname(n-1)*A053669(n) ; end if; end proc: # R. J. Mathar, Jul 06 2011

Mathematica

sp[{n_, a_}]:=Module[{p=2}, While[GCD[n+1, p]!=1, p=NextPrime[p]]; {n+1, a*p}]; NestList[sp, {1, 1}, 30][[All, 2]] (* Harvey P. Dale, May 08 2021 *)

Crossrefs

Cf. A053669.

Sequence in context: A034457 A268529 A026532 * A390839 A081150 A362014

Adjacent sequences: A160502 A160503 A160504 * A160506 A160507 A160508

Keyword

easy,nonn

Author

Masahiko Shin, May 16 2009

Status

approved