The On-Line Encyclopedia of Integer Sequences (OEIS)

Revision History for A324893 (Bold, blue-underlined text is an addition; faded, red-underlined text is a ~~deletion~~.)
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A324893

a(n) = sigma(A097706(n)), where A097706(n) is the part of n composed of prime factors of form 4k+3.
(history; published version)

#13 by Joerg Arndt at Sun Mar 31 02:34:00 EDT 2019

STATUS

reviewed

approved

#12 by Michel Marcus at Sat Mar 30 07:52:53 EDT 2019

STATUS

proposed

reviewed

#11 by Michael De Vlieger at Sat Mar 30 07:22:57 EDT 2019

STATUS

editing

proposed

#10 by Michael De Vlieger at Sat Mar 30 07:22:56 EDT 2019

MATHEMATICA

Array[DivisorSigma[1, Times @@ Power @@@ Select[FactorInteger[#], Mod[#[[1]], 4] == 3 &]] &, 102] (* Michael De Vlieger, Mar 30 2019 *)

STATUS

proposed

editing

#9 by Antti Karttunen at Fri Mar 29 03:50:06 EDT 2019

STATUS

editing

proposed

#8 by Antti Karttunen at Fri Mar 29 03:49:53 EDT 2019

FORMULA

Multiplicative with a(p^e) = (p^(e+1) - 1)/(p-1) if p == 3 (mod 4), otherwise a(p^e) = 1.

STATUS

approved

editing

Discussion

Fri Mar 29

03:50

Antti Karttunen: Quick "post-fix".

#7 by Susanna Cuyler at Thu Mar 28 20:23:24 EDT 2019

STATUS

proposed

approved

#6 by Antti Karttunen at Thu Mar 28 16:37:22 EDT 2019

STATUS

editing

proposed

#5 by Antti Karttunen at Thu Mar 28 04:40:37 EDT 2019

NAME

a(n) = A000203sigma(A097706(n)), where A097706(n) is the part of n composed of prime factors of form 4k+3.

FORMULA

Multiplicative with a(p) = (p^(e+1) - 1)/(p-1) if p == 3 (mod 4), othwerise otherwise a(p^e) = 1.

#4 by Antti Karttunen at Thu Mar 28 04:36:57 EDT 2019

FORMULA

Multiplicative with a(p) = (p^(e+1) - 1)/(p-1) if p == 3 (mod 4), othwerise a(p^e) = 1.