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A056076
Numbers k that divide sigma(k) + d(k), where d(k) is the number of divisors of k and sigma(k) is their sum.
1
1, 3, 14, 52, 60, 130, 184, 656, 5472, 8648, 12008, 34688, 2118656, 2500704, 33721216, 40575616, 59376256, 89397016, 99523456, 134438912, 150441856, 173706136, 283417216, 537346048, 1082640256, 6801628304, 91707741184
OFFSET
1,2
COMMENTS
a(28) > 2*10^11. 14451706793984, 2258918614925312 and 9007202811510784 are also terms. - Donovan Johnson, Feb 10 2012
a(28) > 10^13. - Giovanni Resta, Nov 13 2019
MATHEMATICA
Do[If[Mod[DivisorSigma[1, n]+DivisorSigma[0, n], n]==0, Print[n]], {n, 1, 10^8}]
PROG
(PARI) for(n=1, 10^8, if(Mod((sigma(n)+numdiv(n)), n)==0, print(n)))
CROSSREFS
Sequence in context: A322199 A192882 A351690 * A117133 A238226 A083874
KEYWORD
nonn
AUTHOR
Robert G. Wilson v, Jul 26 2000
EXTENSIONS
Corrected by Jason Earls, Aug 06 2001
Corrected by T. D. Noe, Nov 01 2006
a(25)-a(27) from Donovan Johnson, Dec 07 2008
STATUS
approved