A014509 -id:A014509 - cp's OEIS frontend

A110841 a(n) is the number of prime factors, with multiplicity, of abs(A014509(n)).

0, 0, 0, 0, 0, 0, 0, 0, 1, 4, 2, 7, 7, 2, 2, 4, 3, 3, 7, 1, 6, 4, 5, 14, 4, 9, 5, 10, 3, 11, 2, 5, 3, 7, 11, 5, 3, 4, 15, 6, 5, 19, 10, 6, 13, 15, 5, 10, 5, 5, 6, 7, 5, 15, 7, 5, 2, 13, 4, 3, 10, 5, 9, 7, 5, 4, 9, 5, 4, 1, 7, 4, 4, 5, 3, 11, 13, 10, 5, 5, 7, 6

Offset: 0

Jonathan Vos Post, Sep 16 2005

			a(10) = 2 because A014509(10) = 529 = 23^2.
a(8) = a(19) = 1 since A014509(8) and A014509(19) are prime.

Sean A. Irvine, Table of n, a(n) for n = 0..91

Cf. A001222, A073276, A075178, A076547, A076549, A079294, A083687, A084217, A085092, A085737, A089170, A089644, A089655.

a(n) = my(b=bernfrac(2*n), c=floor(abs(b))*sign(b)); if (c==0, 0, bigomega(c)); \\ Michel Marcus, Mar 29 2020

a(n) = A001222(abs(A014509(n))).

More terms from Michel Marcus, Mar 29 2020
a(51)-a(65) from Jinyuan Wang, Apr 02 2020
More terms from Sean A. Irvine, Jul 29 2024

A134825 Floor of the even-indexed Bernoulli numbers B_{2n} = A000367(n)/A002445(n).

Original entry on oeis.org

1, 0, -1, 0, -1, 0, -1, 1, -8, 54, -530, 6192, -86581, 1425517, -27298232, 601580873, -15116315768, 429614643061, -13711655205089, 488332318973593, -19296579341940069, 841693047573682615, -40338071854059455414, 2115074863808199160560, -120866265222965259346028

Offset: 0

Wolfdieter Lang, Nov 13 2007

			n=4: B_8=-1/30=-0,033... hence a(4)=-1.

C. J. Moreno and S. S. Wagstaff, Jr., Sums of Squares of Integers, Chapman & Hall, 2006, p. 107.

Cf. A000367, A002445, A014509, A027641, A027642.

Floor@BernoulliB[2 Range[0, 20]] (* Vladimir Reshetnikov, Nov 12 2015 *)

vector(30, n, n--; floor(bernfrac(2*n))) \\ Altug Alkan, Nov 12 2015

a(n) = floor(B_(2n)), n>=0, with B_{2n} = A000367(n)/A002445(n) = A027641(2n)/A027642(2n).

cp's OEIS Frontend

A110841 a(n) is the number of prime factors, with multiplicity, of abs(A014509(n)).

Views

Author

Keywords

Examples

Links

Crossrefs

Programs

PARI

Formula

Extensions