Least k such that 10^n + k, 10^n + k + 2, and 10^n + k + 6 are prime.
1, 1, 91, 331, 517, 1087, 451, 2011, 2821, 10687, 2497, 5707, 5557, 20671, 7147, 7357, 45967, 30061, 9157, 26317, 36307, 55027, 65941, 6667, 120631, 70561, 122287, 209881, 94897, 53551, 74551, 301711, 89947, 246871, 246961, 710587, 633451, 117097, 96841
1
T. D. Noe, Plot of 100 terms
T. D. Noe, Table of 100 terms
(Mma) Table[m = 10^n; k = 1; While[! (PrimeQ[m + k] && PrimeQ[m + k + 2] && PrimeQ[m + k + 6]), k = k + 2]; k, {n, 40}]
Cf. A124001, A121066 (similar sequences for twin primes and pairs of twins).
Cf. S000100, S000101.
nonn,hard
T. D. Noe, Jun 25 2014