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Search: id:A065764
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| A065764 |
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Sum of divisors of square numbers. |
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+0
10
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| 1, 7, 13, 31, 31, 91, 57, 127, 121, 217, 133, 403, 183, 399, 403, 511, 307, 847, 381, 961, 741, 931, 553, 1651, 781, 1281, 1093, 1767, 871, 2821, 993, 2047, 1729, 2149, 1767, 3751, 1407, 2667, 2379, 3937, 1723, 5187, 1893, 4123, 3751, 3871, 2257, 6643
(list; graph; listen)
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OFFSET
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1,2
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COMMENT
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Unlike like sigma[2x^2], the sums of divisors of squares give remainders r=1,3,5 modulo 6: sigma[4]==1,sigma[49]==3, sigma[2401]==5 (mod 6). See also A065765 and A097022.
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LINKS
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T. D. Noe, Table of n, a(n) for n=1..10000
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FORMULA
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a(n)=Sigma[n^2]=A000203[A000290(n)]
Multiplicative with a(p^e) = (p^(2*e+1)-1)/(p-1). - Vladeta Jovovic (vladeta(AT)eunet.rs), Dec 01 2001
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PROGRAM
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(MuPad) numlib::sigma(n^2)$ n=1..81 - Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), May 13 2008
(Other) sage: [sigma(n^2, 1)for n in xrange(1, 49)] # [From Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Jun 13 2009]
(PARI) { for (n=1, 10000, write("b065764.txt", n, " ", sigma(n^2)) ) } [From Harry J. Smith (hjsmithh(AT)sbcglobal.net), Oct 30 2009]
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CROSSREFS
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Cf. A028982, A000203, A000290
Sequence in context: A096333 A133325 A063583 this_sequence A073473 A040084 A151723
Adjacent sequences: A065761 A065762 A065763 this_sequence A065765 A065766 A065767
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KEYWORD
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nonn,mult
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AUTHOR
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Labos E. (labos(AT)ana.sote.hu), Nov 19 2001
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