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 A273460 Numbers n such that sum of the divisors of n (except 1 and n) is equal to the product of the digits of n. 1
 98, 101, 103, 107, 109, 307, 329, 401, 409, 503, 509, 601, 607, 701, 709, 809, 907, 1009, 1013, 1019, 1021, 1031, 1033, 1039, 1049, 1051, 1061, 1063, 1069, 1087, 1091, 1093, 1097, 1103, 1109, 1201, 1301, 1303, 1307, 1409, 1601, 1607, 1609, 1709, 1801, 1901 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Or numbers n such that A048050(n) = A007954(n). Most of the terms are primes which have at least one 0 among their digits (A056709). The composite numbers of the sequence are 98, 329, 3383, 4343, 5561, 6623, 12773, 17267, 21479, 57721, 129383, 136259, 142943, 172793, 246959, 256631, 292571,... LINKS Amiram Eldar, Table of n, a(n) for n = 1..10000 EXAMPLE sigma(98) - 98 - 1 = 171 - 98 - 1 = 72 and 8*9 = 72 so 98 is in the sequence. MAPLE with(numtheory): for n from 1 to 3000 do: q:=convert(n, base, 10):n0:=nops(q): pr:=product('q[i]', 'i'=1..n0):p:=sigma(n)-n-1: if p=pr then printf(`%d, `, n): else fi: od: MATHEMATICA Do[If[DivisorSigma[1, n]-n-1==Apply[Times, IntegerDigits[n]], Print[n]], {n, 2000}] Select[Range[2, 2000], Total[Most[Rest[Divisors[#]]]]==Times@@ IntegerDigits[ #]&] (* Harvey P. Dale, Jul 20 2019 *) CROSSREFS Cf. A007954, A048050, A056709, A069675. Sequence in context: A129887 A205067 A307371 * A095605 A095589 A039491 Adjacent sequences: A273457 A273458 A273459 * A273461 A273462 A273463 KEYWORD nonn,base AUTHOR Michel Lagneau, May 23 2016 STATUS approved

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Last modified December 2 23:17 EST 2023. Contains 367526 sequences. (Running on oeis4.)