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 A167409 Very Orderly Numbers: a number, N, is "very orderly" if the set of the divisors of N is congruent to the set {1,2,...,tau(N)} mod tau(N)+1. 6
 1, 2, 5, 8, 11, 12, 17, 20, 23, 27, 29, 38, 41, 47, 52, 53, 57, 58, 59, 68, 71, 72, 76, 83, 87, 89, 101, 107, 113, 117, 118, 124, 131, 133, 137, 149, 158, 162, 164, 167, 173, 177, 178, 179, 188, 191, 197, 203, 218, 227, 233, 236, 237, 239, 243, 244, 247, 251, 257 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS The very orderly numbers are orderly numbers (Cf. A167408) with K = tau(N)+1 LINKS A. Weimholt, Table of n, a(n) for n=1..10000 MATHEMATICA veryOrderlyQ[n_] := (If[tau = DivisorSigma[0, n]; Union[Mod[Divisors[n], tau + 1]] == Range[tau], Return[True]]; False); Select[ Range[260], veryOrderlyQ] (* Jean-François Alcover, Aug 19 2013 *) PROG (PARI) vo(n)=#(n=divisors(n))==#(n=Set(n%(1+#n))) & n[1]!="0" for(n=1, 999, vo(n)&print1(n", ")) \\ M. F. Hasler CROSSREFS Cf. A167408 - Orderly Numbers Cf. A167410 - Disorderly Numbers - numbers not in A167408 Cf. A167411 - Minimal K Values for the Orderly Numbers Sequence in context: A177966 A083422 A187581 * A082406 A215938 A007826 Adjacent sequences:  A167406 A167407 A167408 * A167410 A167411 A167412 KEYWORD nonn AUTHOR Andrew Weimholt, Nov 03 2009 STATUS approved

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Last modified May 11 07:29 EDT 2021. Contains 343784 sequences. (Running on oeis4.)