

A166590


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


21



1, 4, 5, 16, 7, 20, 9, 64, 25, 28, 13, 80, 15, 36, 35, 256, 19, 100, 21, 112, 45, 52, 25, 320, 49, 60, 125, 144, 31, 140, 33, 1024, 65, 76, 63, 400, 39, 84, 75, 448, 43, 180, 45, 208, 175, 100, 49, 1280, 81, 196, 95, 240, 55, 500, 91, 576, 105, 124, 61, 560
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OFFSET

1,2


LINKS

Michael De Vlieger, Table of n, a(n) for n = 1..10000


FORMULA

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


MATHEMATICA

a166590[n_] := {1}~Join~Rest[Times @@ Power @@@ Transpose[{Plus[First /@ FactorInteger@ #, 2], Last /@ FactorInteger@ #}] & /@ Range@n]; a166590[60] (* Michael De Vlieger, Jan 07 2015 *)


PROG

(PARI) a(n) = my(f=factor(n)); for (i=1, #f~, f[i, 1] += 2); factorback(f); \\ Michel Marcus, Jun 09 2014


CROSSREFS

Sequence in context: A323627 A289742 A249113 * A244643 A085768 A166304
Adjacent sequences: A166587 A166588 A166589 * A166591 A166592 A166593


KEYWORD

nonn,mult


AUTHOR

Jaroslav Krizek, Oct 17 2009


EXTENSIONS

More terms from Michel Marcus, Jun 09 2014


STATUS

approved



