A071350 Distinct values of A058250; these terms appear first at subscripts listed in A071349.

1, 2, 6, 30, 330, 2310, 53130, 690690, 20030010, 821230410, 13960916970, 739928599410, 27377358178170, 2272320728788110, 97709791337888730, 8696171429072096970, 165227257152369842430, 18670680058217792194590

Offset: 1

Author

Labos Elemer, May 21 2002

Keywords

• nonn
• easy

Links

• Michael De Vlieger, Table of n, a(n) for n = 1..341

Crossrefs

Cf. A058250, A002110, A000010, A005867, A071349, A112037.

Programs

Mathematica

Prepend[FoldList[Times,DeleteDuplicates[Rest[Flatten[FactorInteger[#][[All, 1]]&/@(Prime[Range[100]]-1)]]]],1] (* Jamie Morken, Apr 27 2021 after Harvey P. Dale at A112037, May 26 2019 *)

PARI

f(n) = my(pr=prod(k=1, n, prime(k))); gcd(pr, eulerphi(pr)); \\ A058250
lista(nn) = Set(vector(nn, k, f(k))); \\ Michel Marcus, Apr 27 2021

Formula

a(n) = a(n-1) * A112037(n), n >= 2. - David A. Corneth, Apr 27 2021