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A064971
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n*usigma(n), where usigma(n) is the sum of unitary divisors of n (A034448).
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1
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1, 6, 12, 20, 30, 72, 56, 72, 90, 180, 132, 240, 182, 336, 360, 272, 306, 540, 380, 600, 672, 792, 552, 864, 650, 1092, 756, 1120, 870, 2160, 992, 1056, 1584, 1836, 1680, 1800, 1406, 2280, 2184, 2160, 1722, 4032, 1892, 2640, 2700, 3312, 2256
(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
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FORMULA
| Multiplicative with a(p^e) = p^e*(p^e+1). - Vladeta Jovovic (vladeta(AT)eunet.rs), Nov 01 2001
Dirichlet g.f. zeta(s-1)*zeta(s-2)/zeta(2*s-3). - R. J. Mathar, Feb 09 2011
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MAPLE
| seq(mul(ifactors(n)[2][i][1]^ifactors(n)[2][i][2]*(1+ifactors(n)[2][i][1]^ifactors(n)[2][i][2]), i=1..nops(ifactors(n)[2])), n=1..50);
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PROG
| (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) } { for (n=1, 1000, write("b064971.txt", n, " ", n*usigma(n)) ) } [From Harry J. Smith (hjsmithh(AT)sbcglobal.net), Oct 01 2009]
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CROSSREFS
| Sequence in context: A007622 A180291 A056930 * A130199 A117343 A028611
Adjacent sequences: A064968 A064969 A064970 * A064972 A064973 A064974
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KEYWORD
| mult,nonn
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AUTHOR
| N. J. A. Sloane (njas(AT)research.att.com), Oct 30 2001
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