A122712 Least prime p of a quartet of 4 distinct primes {p, p+2, q, q+2} such that each digit of q is the same as the corresponding digit of p except that each 6 in p corresponds to a 9 in q and vice versa.

1061, 1667, 14561, 16691, 17657, 19961, 36341, 55631, 56207, 60167, 60917, 61151, 62981, 64151, 67577, 68711, 68897, 69737, 76367, 76961, 79691, 90617, 92681, 96737, 98867, 100361, 106451, 115601, 136397, 136991, 139367, 139661, 146057, 155861, 156677, 165047, 167267, 167861, 186647

Offset

1,1

Links

Table of n, a(n) for n=1..39.

Example

16691 and 16693 are twin primes, as are 19961 and 19963, so 16691 is a term.

Prog

(PARI) f(d) = my(ok=0); for (i=1, #d, if (d[i]==6, ok=1; d[i]=9, if (d[i]==9, d[i]=6))); if (ok, fromdigits(d));
isok(p) = {if (isprime(p) && isprime(p+2), my(q=f(digits(p))); isprime(q) && isprime(q+2); ); } \\ Michel Marcus, May 16 2022

Crossrefs

Subsequence of A001359.

Sequence in context: A048895 A020374 A142822 * A172384 A177136 A080334

Adjacent sequences: A122709 A122710 A122711 * A122713 A122714 A122715

Keyword

base,nonn

Author

Pierre CAMI, Sep 23 2006

Extensions

Corrected and extended by Michel Marcus, May 16 2022

Status

approved