The On-Line Encyclopedia of Integer Sequences (OEIS)

Revision History for A328639 (Bold, blue-underlined text is an addition; faded, red-underlined text is a ~~deletion~~.)
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A328639

Dirichlet g.f.: zeta(2*s) / (zeta(s) * zeta(s-2)).
(history; published version)

#13 by Joerg Arndt at Mon Nov 30 03:58:01 EST 2020

STATUS

reviewed

approved

#12 by Michel Marcus at Mon Nov 30 02:33:33 EST 2020

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proposed

reviewed

#11 by Amiram Eldar at Mon Nov 30 02:03:52 EST 2020

STATUS

editing

proposed

#10 by Amiram Eldar at Mon Nov 30 01:50:17 EST 2020

FORMULA

Multiplicative with a(p^e) = (-1)^e*(p^2 + 1). - Amiram Eldar, Nov 30 2020

MATHEMATICA

f[p_, e_] := (-1)^e*(p^2 + 1); a[1] = 1; a[n_] := Times @@ (f @@@ FactorInteger[n]); Array[a, 100] (* Amiram Eldar, Nov 30 2020 *)

#9 by Amiram Eldar at Mon Nov 30 01:48:36 EST 2020

LINKS

Amiram Eldar, <a href="/A328639/b328639.txt">Table of n, a(n) for n = 1..10000</a>

STATUS

approved

editing

#8 by Alois P. Heinz at Fri Oct 25 21:48:50 EDT 2019

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proposed

approved

#7 by Andrew Howroyd at Fri Oct 25 21:40:13 EDT 2019

STATUS

editing

proposed

#6 by Andrew Howroyd at Fri Oct 25 21:40:05 EDT 2019

PROG

(PARI) a(n)={sumdiv(n, d, (-1)^bigomega(n/d)*moebius(d)*d^2)} \\ Andrew Howroyd, Oct 25 2019

STATUS

proposed

editing

#5 by Ilya Gutkovskiy at Wed Oct 23 02:25:06 EDT 2019

STATUS

editing

proposed

#4 by Ilya Gutkovskiy at Wed Oct 23 02:10:57 EDT 2019

CROSSREFS

Cf. A008683, A008836, A026424 (positions of negative terms), A046970, A065958, A323363, A328640.