

A238730


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


2



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
(list;
graph;
refs;
listen;
history;
text;
internal format)



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



