

A103851


Numbers k such that 2*prime(k)+1, 2*prime(k+1)+1 and 2*prime(k+2)1 are also consecutive primes.


2



2, 119, 372, 814, 4350, 9797, 16625, 16729, 40224, 45191, 48121, 63137, 71520, 83264, 89744, 94166, 103551, 109538, 111283, 113690, 117620, 232363, 265101, 268661, 269466, 302024, 316847, 329793, 333947, 334725, 340910, 352997, 380914, 381169, 384459, 385927
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OFFSET

1,1


LINKS



EXAMPLE

2*3+1 = 5, 2*5+1 = 7, 2*7  1 = 13; 3, 5 and 7 are consecutive primes as are 5, 7 and 13, so a(1) = 2 as 3 = prime(2).


MATHEMATICA

s={}; n=1; p1=2; p2=3; Do[p3 = NextPrime[p2]; If[PrimeQ[2*p1+1] && (np = NextPrime[2*p1+1]) == 2*p2+1 && NextPrime[np] == 2*p31, AppendTo[s, n]]; p1=p2; p2=p3; n++, {10^5}]; s (* Amiram Eldar, Jul 23 2021 *)


CROSSREFS



KEYWORD

nonn


AUTHOR



EXTENSIONS

a(21) and a(30) inserted and a(36) added by Amiram Eldar, Jul 23 2021


STATUS

approved



