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A063731
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Numbers n such that Sum_{k=1..n} sigma(k) divides Prod_{k=1..n} sigma(k).
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1
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1, 5, 8, 15, 50, 52, 53, 55, 63, 68, 72, 96, 103, 157, 176, 196, 211, 219, 287, 288, 302, 303, 321, 327, 348, 360, 364, 365, 381, 402, 417, 421, 430, 431, 438, 444, 452, 454, 465, 472, 478, 504, 506, 512, 514, 530, 531, 534, 555, 565, 576, 584, 588, 594, 607
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,2
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LINKS
| Harry J. Smith, Table of n, a(n) for n=1,...,1000
Matthew M. Conroy, Home page (listed instead of email address)
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PROG
| (PARI) for(n=1, 300, a=sum(k=1, n, sigma(k)); b=prod(k=1, n, sigma(k)); if(Mod(b, a)==0, print(n)))
(PARI) { n=0; a=0; b=1; for (m=1, 10^9, a+=sigma(m); b*=sigma(m); if (b%a==0, write("b063731.txt", n++, " ", m); if (n==1000, break)) ) } [From Harry J. Smith (hjsmithh(AT)sbcglobal.net), Aug 28 2009]
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CROSSREFS
| Sequence in context: A164094 A112269 A091574 * A129316 A039752 A141536
Adjacent sequences: A063728 A063729 A063730 * A063732 A063733 A063734
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KEYWORD
| easy,nonn
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AUTHOR
| Jason Earls (zevi_35711(AT)yahoo.com), Aug 12 2001
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EXTENSIONS
| More terms from Matthew M. Conroy, Aug 21 2001
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