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 A055720 Numbers k such that d(k)+1 | k. 1
 3, 4, 10, 15, 28, 35, 54, 55, 63, 64, 65, 85, 95, 98, 100, 115, 125, 135, 144, 145, 147, 155, 156, 175, 176, 185, 189, 205, 215, 234, 235, 245, 260, 265, 295, 297, 305, 335, 336, 351, 355, 364, 365, 395, 400, 408, 415, 416, 445, 459, 485 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Integers divisible by 1 more than the number of their divisors. The only prime is 3. These numbers cannot be very orderly numbers (A167409). - T. D. Noe, Nov 13 2009 LINKS Amiram Eldar, Table of n, a(n) for n = 1..10000 MATHEMATICA Select[Range[1000], Mod[ #, 1 + DivisorSigma[0, # ]] == 0 &] PROG (PARI) isok(k) = Mod(k, numdiv(k)+1) == 0; \\ Michel Marcus, Mar 12 2020 CROSSREFS Cf. A000005, A167409. Sequence in context: A204292 A218277 A103080 * A054184 A307057 A188022 Adjacent sequences:  A055717 A055718 A055719 * A055721 A055722 A055723 KEYWORD nonn AUTHOR Robert G. Wilson v, Jun 09 2000 EXTENSIONS Edited by T. D. Noe, Nov 13 2009 STATUS approved

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Last modified August 17 23:13 EDT 2022. Contains 356204 sequences. (Running on oeis4.)