A166660 Totally multiplicative sequence with a(p) = 2p+1 for prime p.

1, 5, 7, 25, 11, 35, 15, 125, 49, 55, 23, 175, 27, 75, 77, 625, 35, 245, 39, 275, 105, 115, 47, 875, 121, 135, 343, 375, 59, 385, 63, 3125, 161, 175, 165, 1225, 75, 195, 189, 1375, 83, 525, 87, 575, 539, 235, 95, 4375, 225, 605

Offset

1,2

Links

G. C. Greubel, Table of n, a(n) for n = 1..10000

Formula

Multiplicative with a(p^e) = (2p+1)^e. If n = Product p(k)^e(k) then a(n) = Product (2*p(k)+1)^e(k).

Mathematica

a[1] = 1; a[n_] := (fi = FactorInteger[n]; Times @@ ((2*fi[[All, 1]] + 1)^fi[[All, 2]]) ); Table[a[n], {n, 1, 100}](* G. C. Greubel, May 21 2016 *)

Crossrefs

Sequence in context: A025108 A298900 A357852 * A354202 A037374 A056717

Adjacent sequences: A166657 A166658 A166659 * A166661 A166662 A166663

Keyword

nonn,mult

Author

Jaroslav Krizek, Oct 18 2009

Status

approved