login
Filter-sequence for factorial base (cycles in A060117/A060118-permutations): Least number with the same prime signature as A275725.
6

%I #18 Nov 19 2016 08:28:00

%S 2,4,12,8,12,8,60,36,24,16,24,16,60,24,24,16,36,16,60,24,36,16,24,16,

%T 420,180,180,72,180,72,120,72,48,32,48,32,120,48,48,32,72,32,120,48,

%U 72,32,48,32,420,180,120,48,120,48,120,72,48,32,48,32,180,72,48,32,72,32,180,72,72,32,48,32,420,120,120,48,180,48,180,72,48,32,72,32,120,48,48

%N Filter-sequence for factorial base (cycles in A060117/A060118-permutations): Least number with the same prime signature as A275725.

%C This sequence can be used for filtering certain sequences related to cycle-structures in finite permutations as ordered by lists A060117 / A060118 (and thus also related to factorial base representation, A007623) because it matches only with any such sequence b that can be computed as b(n) = f(A275725(n)), where f(n) is any function that depends only on the prime signature of n (some of these are listed under the index entry for "sequences computed from exponents in ...").

%C Matching in this context means that the sequence a matches with the sequence b iff for all i, j: a(i) = a(j) => b(i) = b(j). In other words, iff the sequence b partitions the natural numbers to the same or coarser equivalence classes (as/than the sequence a) by the distinct values it obtains.

%H Antti Karttunen, <a href="/A278225/b278225.txt">Table of n, a(n) for n = 0..40319</a>

%H <a href="/index/Eu#epf">Index entries for sequences computed from exponents in factorization of n</a>

%H <a href="/index/Fa#facbase">Index entries for sequences related to factorial base representation</a>

%F a(n) = A046523(A275725(n)).

%o (Scheme) (define (A278225 n) (A046523 (A275725 n)))

%Y Cf. A007623, A060117, A060118, A046523, A275725.

%Y Other filter-sequences related to factorial base: A278234, A278235, A278236.

%Y Sequences that partition N into same or coarser equivalence classes: A048764, A048765, A060129, A060130, A060131, A084558, A275803, A275851, A257510.

%K nonn

%O 0,1

%A _Antti Karttunen_, Nov 16 2016