A166662 Totally multiplicative sequence with a(p) = 4p+1 for prime p.

1, 9, 13, 81, 21, 117, 29, 729, 169, 189, 45, 1053, 53, 261, 273, 6561, 69, 1521, 77, 1701, 377, 405, 93, 9477, 441, 477, 2197, 2349, 117, 2457, 125, 59049, 585, 621, 609, 13689, 149, 693, 689, 15309, 165, 3393, 173, 3645, 3549, 837, 189, 85293, 841, 3969

Offset: 1

Author

Jaroslav Krizek, Oct 18 2009

Keywords

• nonn
• mult

Links

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

Programs

Mathematica

a[1] = 1; a[n_] := (fi = FactorInteger[n]; Times @@ ((4*fi[[All, 1]] + 1)^fi[[All, 2]])); Table[a[n], {n, 1, 100}] (* G. C. Greubel, May 22 2016 *)

Formula

Multiplicative with a(p^e) = (4p+1)^e. If n = Product p(k)^e(k) then a(n) = Product (4*p(k)+1)^e(k).