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A278251
Least number with the prime signature of the n-th central polygonal number.
4
1, 1, 2, 2, 2, 6, 2, 2, 6, 2, 6, 6, 6, 2, 6, 2, 2, 30, 2, 8, 6, 2, 2, 12, 6, 2, 30, 6, 2, 6, 6, 12, 6, 6, 2, 6, 6, 6, 30, 2, 6, 6, 2, 6, 6, 6, 6, 30, 6, 6, 30, 2, 6, 6, 6, 2, 30, 6, 2, 30, 2, 6, 30, 2, 6, 30, 6, 2, 60, 12, 2, 6, 2, 6, 6, 30, 2, 6, 2, 2, 60, 2, 30, 6, 6, 6, 6, 6, 30, 30, 2, 2, 6, 6, 6, 30, 6, 6, 6, 6, 2, 210, 2, 30, 6, 6, 2, 30, 30, 6, 30, 2, 2
OFFSET
0,3
COMMENTS
Almost all terms seem to be primorials, 4871 of the first 5212, in other words, most terms of A002061 (in the same range) are squarefree.
LINKS
FORMULA
a(n) = A046523(A002061(n)).
PROG
(Scheme) (define (A278251 n) (A046523 (A002061 n)))
CROSSREFS
Cf. also A278246, A278247, A278253.
Sequence in context: A167568 A361301 A240501 * A286847 A291439 A023957
KEYWORD
nonn
AUTHOR
Antti Karttunen, Nov 21 2016
STATUS
approved