A238730 The largest prime in each decade (10k,10k+10) containing at least three primes.

7, 19, 47, 79, 109, 139, 199, 229, 317, 439, 467, 619, 647, 829, 859, 887, 1039, 1069, 1097, 1307, 1429, 1459, 1489, 1609, 1669, 1699, 1789, 1879, 1999, 2089, 2389, 2689, 2719, 3169, 3259, 3469, 3677, 3769, 3919, 4007, 4099, 4159, 4219, 4519, 4729, 4789, 4937, 5237, 5419, 5449, 5479, 5507, 5659, 5749, 5869, 6709, 6829

Offset

1,1

Comments

The initial term 7 does not correspond to a "decadal prime triple" according to the strict definition of A008470.

Links

Robert Israel, Table of n, a(n) for n = 1..10000

Maple

f:= proc(k) local P;
   P:= select(isprime, [10*k+1, 10*k+3, 10*k+7, 10*k+9]);
   if nops(P) >= 3 then max(P) fi
end proc:f(0):= 7:map(f, [$0..1000]); # Robert Israel, Jun 08 2020

Prog

(PARI) p=0; for(d=1, 999, 2+p < (p=primepi(10*d)) && print1(precprime(d*10)", "))

Crossrefs

Cf. A008470, A008471, A238713, A238715.

Sequence in context: A277613 A278403 A143128 * A139865 A146403 A000491

Adjacent sequences: A238727 A238728 A238729 * A238731 A238732 A238733

Keyword

nonn

Author

M. F. Hasler, Mar 03 2014

Status

approved