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Search: id:A064443
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| A064443 |
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usigma(n) is a square and sets a new record for such squares. |
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+0
1
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| 1, 3, 8, 22, 66, 170, 210, 490, 510, 930, 1470, 2130, 2910, 3810, 5406, 5970, 7230, 7590, 10110, 12306, 13470, 14322, 17310, 17490, 23142, 26430, 29010, 32430, 37470, 42546, 44814, 49170, 58674, 69330, 73830, 86610, 87780, 96690
(list; graph; listen)
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OFFSET
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1,2
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LINKS
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Harry J. Smith, Table of n, a(n) for n=1,...,100
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PROGRAM
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(PARI) usigma(n, s=1, fac, i) = fac=factor(n); for(i=1, matsize(fac)[1], s=s*(1+fac[i, 1]^fac[i, 2])); return(s); a=0; j=[]; for(n=1, 10^5, x=usigma(n); if(issquare(x), b=x; if(b>a, a=b; j=concat(j, n)))); j
(PARI) usigma(n)= { local(f, s=1); f=factor(n); for(i=1, matsize(f)[1], s*=1 + f[i, 1]^f[i, 2]); return(s) } { n=a=0; for (m=1, 10^9, if (issquare(b=usigma(m)), if(b>a, a=b; write("b064443.txt", n++, " ", m); if (n==100, break))) ) } [From Harry J. Smith (hjsmithh(AT)sbcglobal.net), Sep 14 2009]
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CROSSREFS
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Cf. A034448.
Sequence in context: A099324 A117420 A003101 this_sequence A000732 A092090 A011958
Adjacent sequences: A064440 A064441 A064442 this_sequence A064444 A064445 A064446
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KEYWORD
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nonn
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AUTHOR
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Jason Earls (zevi_35711(AT)yahoo.com), Oct 01 2001
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