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A098064
Least k such that k*prime(n)#/6 - 6 and k*prime(n)#/6 + 6 are consecutive primes with gap of 12 for n > 2.
4
41, 43, 19, 25, 29, 119, 35, 73, 83, 337, 193, 71, 137, 7, 515, 731, 53, 211, 353, 247, 1415, 65, 223, 77, 481, 191, 331, 367, 605, 769, 77, 1751, 221, 617, 713, 683, 1325, 233, 187, 259, 641, 235, 545, 2761, 1993, 71, 851, 527, 1159, 757, 239, 1817, 3203
OFFSET
3,1
EXAMPLE
43*prime(4)#/6-6 = 43*2*3*5*7/6-6 = 1499, 43*prime(4)#/6+6 = 43*2*3*5*7/6+6 = 1511, 1499 and 1511 are consecutive primes with gap of 12, so a(4) = 43.
MATHEMATICA
a[n_] := Module[{k = 1, p = Product[Prime[i], {i, 1, n}]}, While[!(PrimeQ[k*p/6-6] && NextPrime[k*p/6-6] == k*p/6+6), k++]; k]; Array[a, 60, 3] (* Amiram Eldar, Jul 17 2021 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Pierre CAMI, Sep 11 2004
STATUS
approved