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A278241 Least number with the same prime signature as the n-th partition number: a(n) = A046523(A000041(n)). 6

%I #25 Feb 24 2020 08:58:31

%S 1,1,2,2,2,2,2,6,6,30,30,24,6,2,24,48,30,24,30,60,30,360,30,6,180,30,

%T 420,210,60,30,60,30,60,180,30,60,2,30,60,1680,420,210,30,240,60,30,

%U 210,420,30,60,30,60,2310,60,2310,420,30,30,420,4620,30,2310,420,30,2310,6,6720,6,420,30,3360,30,30,30,2520,120120,6,2,420,420,1260,6,840,30,4620,12

%N Least number with the same prime signature as the n-th partition number: a(n) = A046523(A000041(n)).

%C This sequence works as a "sentinel" for partition numbers by matching to any sequence that is obtained as f(A000041(n)), where f(n) is any function that depends only on the prime signature of n (see the index entry for "sequences computed from exponents in ..."). The last line in Crossrefs section lists such sequences that were present in the database as of Nov 11 2016.

%H Amiram Eldar, <a href="/A278241/b278241.txt">Table of n, a(n) for n = 0..10000</a> (terms 0..2527 from Antti Karttunen)

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

%F a(n) = A046523(A000041(n)).

%o (PARI)

%o A046523(n) = my(f=vecsort(factor(n)[, 2], , 4), p); prod(i=1, #f, (p=nextprime(p+1))^f[i]) \\ From _Charles R Greathouse IV_, Aug 17 2011

%o A278241(n) = A046523(numbpart(n));

%o for(n=0, 2310, write("b278241.txt", n, " ", A278241(n)));

%o (Scheme) (define (A278241 n) (A046523 (A000041 n)))

%Y Cf. A000041, A046523, A278245, A278248.

%Y Sequences that partition N into same or coarser equivalence classes: A085543, A085561, A087175.

%K nonn

%O 0,3

%A _Antti Karttunen_, Nov 16 2016

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Last modified August 14 01:00 EDT 2024. Contains 375146 sequences. (Running on oeis4.)