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Search: id:A065765
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| A065765 |
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Sum of divisors of twice square numbers. |
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+0
6
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| 3, 15, 39, 63, 93, 195, 171, 255, 363, 465, 399, 819, 549, 855, 1209, 1023, 921, 1815, 1143, 1953, 2223, 1995, 1659, 3315, 2343, 2745, 3279, 3591, 2613, 6045, 2979, 4095, 5187, 4605, 5301, 7623, 4221, 5715, 7137, 7905, 5169, 11115, 5679, 8379, 11253
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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The sum of divisors of 2m^2 [twice a square] always gives remainder r = 3 modulo 6. See 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[2*n^2]=A000203[2*A000290(n)]
a(n)=3*A065766(n)
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PROGRAM
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(PARI) { for (n=1, 10000, write("b065765.txt", n, " ", sigma(2*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: A161738 A062741 A117561 this_sequence A146853 A014309 A096742
Adjacent sequences: A065762 A065763 A065764 this_sequence A065766 A065767 A065768
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KEYWORD
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nonn
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AUTHOR
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Labos E. (labos(AT)ana.sote.hu), Nov 19 2001
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