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A063700 Solutions to Sigma[x+d[x]] = Sigma[x]+d[x], where Sigma[] = A000203(), d[] = A000005(). +0
1
3, 5, 11, 17, 29, 41, 59, 71, 101, 107, 137, 147, 149, 179, 191, 197, 227, 239, 269, 281, 311, 347, 419, 431, 461, 521, 569, 596, 599, 617, 641, 659, 809, 821, 827, 857, 881, 1019, 1031, 1049, 1061, 1091, 1151, 1229, 1277, 1289, 1301, 1319, 1427, 1451, 1481 (list; graph; listen)
OFFSET

1,1

LINKS

Harry J. Smith, Table of n, a(n) for n=1,...,1000

EXAMPLE

Primes and composites among solutions: x = 59, d(59) = 2,Sigma(59) = 60,Sigma(59+2) = Sigma(61) = 62 = Sigma(59)+d(59); x = 596, d(596) = 6,Sigma(596) = 1050,Sigma(596+6) = Sigma(602) = 1056 = Sigma(596)+d(596).

PROGRAM

(PARI) { n=0; for (x=1, 10^9, if (sigma(x + numdiv(x)) == (sigma(x) + numdiv(x)), write("b063700.txt", n++, " ", x); if (n==1000, break)) ) } [From Harry J. Smith (hjsmithh(AT)sbcglobal.net), Aug 28 2009]

CROSSREFS

A000005, A000203.

Sequence in context: A144105 A141262 A069233 this_sequence A078859 A054799 A001359

Adjacent sequences: A063697 A063698 A063699 this_sequence A063701 A063702 A063703

KEYWORD

nonn

AUTHOR

Labos E. (labos(AT)ana.sote.hu), Aug 23 2001

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Last modified December 13 23:45 EST 2009. Contains 170824 sequences.


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