A098240 - OEIS

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A098240

Numbers k such that gcd(2k+1, numerator(Bernoulli(4k+2))) is squarefree.

1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 61, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,2

LINKS

Amiram Eldar, Table of n, a(n) for n = 1..10000

MATHEMATICA

Select[Range[80], SquareFreeQ[GCD[2#+1, BernoulliB[4#+2]]]&] (* Harvey P. Dale, Jul 23 2013 *)

PROG

(PARI) for(n=1, 3000, if(issquarefree(gcd(2*n+1, numerator(bernfrac(4*n+2)))), print1(n", "))) \\ Herman Jamke (hermanjamke(AT)fastmail.fm), Nov 02 2006

CROSSREFS

Complement of A098242.

Cf. A005117, A027641, A027642.

Sequence in context: A353838 A183224 A357862 * A023805 A168186 A353866

Adjacent sequences: A098237 A098238 A098239 * A098241 A098242 A098243

KEYWORD

nonn

AUTHOR

Ralf Stephan, Sep 01 2004

STATUS

approved