A343390 a(n) = 1 + Product_{d|n, d < n} a(d).

2, 3, 3, 7, 3, 19, 3, 43, 7, 19, 3, 2395, 3, 19, 19, 1807, 3, 2395, 3, 2395, 19, 19, 3, 246546091, 7, 19, 43, 2395, 3, 370387, 3, 3263443, 19, 19, 19, 96124306951, 3, 19, 19, 246546091, 3, 370387, 3, 2395, 2395, 19, 3, 109838449356687381331, 7, 2395, 19, 2395, 3, 246546091, 19

Offset

1,1

Links

Seiichi Manyama, Table of n, a(n) for n = 1..959

Formula

a(p^k) = A000058(k) for p prime.

Maple

a:= proc(n) option remember;
      1+mul(a(d), d=numtheory[divisors](n) minus {n})
    end:
seq(a(n), n=1..55);  # Alois P. Heinz, Apr 13 2021

Mathematica

a[n_] := a[n] = 1 + Product[If[d < n, a[d], 1], {d, Divisors[n]}]; Table[a[n], {n, 55}]

Crossrefs

Cf. A000058, A067824, A068334.

Sequence in context: A082910 A023646 A056225 * A105437 A323952 A168140

Adjacent sequences: A343387 A343388 A343389 * A343391 A343392 A343393

Keyword

nonn

Author

Ilya Gutkovskiy, Apr 13 2021

Status

approved