A307882 Records of the offset k in A307881, divided by 3.

-1, 1, 3, 5, 7, 9, 11, 13, 15, 25, 29, 31, 39, 45, 61, 63, 75, 81, 85, 111, 123, 131, 151, 175, 207, 225, 241, 267, 301, 329, 335, 427, 435, 505, 539, 565, 611, 617, 665, 695, 739, 805, 843, 875, 1113, 1143, 1465, 1797, 1801, 1959, 2065, 2369, 2783

Offset

1,3

Comments

The divisibility of k by 3 of all terms after a(1) is conjectural. Offsets not divisible by 3 are given as -k instead of k/3.

Links

Table of n, a(n) for n=1..53.

Prog

(PARI) kmax=0; for(n=2, 10^7, forstep(k=1, n, 2, if(isprime(2*n-k)&&isprime(2*n+k), if(k>kmax, if(k%3!=0, print1(-k, ", "), print1(k/3, ", ")); kmax=k); break(1))))

Crossrefs

Cf. A065978, A293858, A307881, A325142.

Sequence in context: A081110 A143449 A033034 * A391853 A185189 A247428

Adjacent sequences: A307879 A307880 A307881 * A307883 A307884 A307885

Keyword

sign,more

Author

Hugo Pfoertner, May 03 2019

Status

approved