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A064112
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Numbers n such that sopf(n) = 2*sopf(n+1), where sopf(n)=A008472.
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1
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99, 155, 689, 1106, 1517, 1524, 3014, 3403, 3479, 5809, 6478, 6723, 8606, 9143, 9454, 9797, 10126, 11771, 12283, 12382, 13112, 13969, 14150, 17422, 19303, 22184, 24856, 27466, 28119, 28529, 35927, 36464, 37512, 41904, 44505, 45016, 45506
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,1
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LINKS
| Harry J. Smith, Table of n, a(n) for n=1,...,600
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EXAMPLE
| sopf(689)=66, 2*sopf(690)=66.
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PROG
| (PARI) sopf(n, s, fac, i) = fac=factor(n); for(i=1, matsize(fac)[1], s=s+fac[i, 1]); return(s); j=[]; for(n=1, 50000, if(sopf(n)==2*sopf(n+1), j=concat(j, n))); j
(PARI) sopf(n)= { local(f, s=0); f=factor(n); for(i=1, matsize(f)[1], s+=f[i, 1]); return(s) } { n=0; sm=sopf(1); for (m=1, 10^9, sp=sopf(m + 1); if (sm==2*sp, write("b064112.txt", n++, " ", m); if (n==600, break)); sm=sp ) } [From Harry J. Smith (hjsmithh(AT)sbcglobal.net), Sep 07 2009]
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CROSSREFS
| Sequence in context: A039446 A165603 A095420 * A185498 A126230 A055164
Adjacent sequences: A064109 A064110 A064111 * A064113 A064114 A064115
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KEYWORD
| nonn
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AUTHOR
| Jason Earls (zevi_35711(AT)yahoo.com), Sep 08 2001
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