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A204617 Multiplicative with a(p^e) = p^(e-1)*H(p). H(2)=1, H(p) = p-1 if p=1 (mod 4) and H(p) = p+1 if p=3 (mod 4). 0
1, 1, 4, 2, 4, 4, 8, 4, 12, 4, 12, 8, 12, 8, 16, 8, 16, 12, 20, 8, 32, 12, 24, 16, 20, 12, 36, 16, 28, 16, 32, 16, 48, 16, 32, 24, 36, 20, 48, 16, 40, 32, 44, 24, 48, 24, 48, 32, 56, 20, 64, 24, 52, 36, 48, 32, 80, 28, 60, 32, 60, 32, 96, 32, 48, 48, 68, 32 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

COMMENTS

a(n) = phi(n) if n is in A072437.

LINKS

Table of n, a(n) for n=1..68.

MATHEMATICA

ar[p_, s_] := Which[Mod[p, 4]==1, p^(s-1)*(p-1), Mod[p, 4]==3, p^(s-1)*(p+1), True, p^(s-1)]; arit[1] = 1; arit[n_] := Product[ar[FactorInteger[n][[i, 1]], FactorInteger[n][[i, 2]]], {i, Length[FactorInteger[n]]}]; Array[arit, 100]

CROSSREFS

Sequence in context: A057696 A057697 A019921 * A061469 A222641 A258852

Adjacent sequences:  A204614 A204615 A204616 * A204618 A204619 A204620

KEYWORD

nonn,mult

AUTHOR

José María Grau Ribas, Jan 17 2012

STATUS

approved

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Last modified October 19 03:54 EDT 2019. Contains 328211 sequences. (Running on oeis4.)