A278246 -id:A278246 - cp's OEIS frontend

A278247 a(n) = least number with the same prime signature as n + (n+1)^2.

1, 2, 2, 2, 2, 2, 6, 2, 2, 2, 2, 6, 2, 6, 2, 2, 6, 6, 2, 2, 2, 6, 6, 2, 6, 2, 6, 2, 6, 2, 2, 6, 6, 6, 2, 8, 6, 2, 2, 6, 2, 12, 6, 2, 2, 2, 30, 2, 6, 2, 6, 30, 2, 2, 2, 2, 6, 6, 2, 2, 6, 30, 6, 2, 2, 2, 6, 2, 6, 2, 6, 6, 6, 6, 6, 2, 6, 6, 6, 30, 6, 6, 2, 12, 2, 2, 6, 6, 2, 6, 6, 30, 2, 2, 6, 2, 6, 6, 6, 2, 2, 30, 2, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 2, 2, 6, 30, 6, 6

Offset: 0

Antti Karttunen, Nov 21 2016

nonn

Almost all terms seem to be primorials, 4848 of the first 5000, in other words, most terms of A028387 (in the same range) are squarefree.

Antti Karttunen, Table of n, a(n) for n = 0..5000

Cf. A028387, A046523.

Cf. also A278246, A278251, A278253, A278255.

(define (A278247 n) (A046523 (A028387 n)))

a(n) = A046523(A028387(n)).

A278251 Least number with the prime signature of the n-th central polygonal number.

Original entry on oeis.org

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

Antti Karttunen, Nov 21 2016

nonn

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.

Antti Karttunen, Table of n, a(n) for n = 0..5211

Cf. A002061, A046523.

Cf. also A278246, A278247, A278253.

(define (A278251 n) (A046523 (A002061 n)))

a(n) = A046523(A002061(n)).

A278255 Least number with the prime signature of the n-th pentagonal number.

Original entry on oeis.org

1, 2, 12, 6, 6, 6, 30, 12, 12, 6, 48, 210, 6, 6, 210, 24, 12, 12, 60, 30, 30, 30, 30, 60, 12, 30, 1080, 30, 6, 30, 30, 240, 60, 6, 420, 60, 30, 6, 210, 420, 6, 120, 192, 30, 60, 6, 210, 840, 12, 12, 420, 210, 6, 120, 210, 60, 210, 6, 120, 210, 30, 30, 420, 96, 30, 30, 180, 210, 30, 210, 30, 1260, 6, 30, 5040, 30, 210, 30, 30, 120, 144, 60, 60, 210, 30, 6, 2310

Offset: 1

Antti Karttunen, Nov 21 2016

nonn

Antti Karttunen, Table of n, a(n) for n = 1..10000

Cf. A000326, A046523.

Cf. also A278246, A278247, A278251, A278253, A278254.

(define (A278255 n) (A046523 (A000326 n)))

a(n) = A046523(A000326(n)).

cp's OEIS Frontend

A278247 a(n) = least number with the same prime signature as n + (n+1)^2.

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A278251 Least number with the prime signature of the n-th central polygonal number.

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A278255 Least number with the prime signature of the n-th pentagonal number.

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