OFFSET
1,1
LINKS
Chai Wah Wu, Table of n, a(n) for n = 1..10000 (n = 1..699 from Robert Israel)
EXAMPLE
a(3) = 11 is a member because it is the lesser of the twin prime pair (11,13), and prime(11) = 31 and prime(13) = 41 are both twin primes.
MAPLE
P:= select(isprime, [2, seq(i, i=3..2*10^5, 2)]):
nP:= nops(P):
T:= P[select(i-> P[i+1]=P[i]+2, [$1..nP-1])]:
TS:= select(`<=`, T, nP-3):
select(t -> (P[t]+2=P[t+1] or P[t]-2=P[t-1]) and (P[t+2]+2=P[t+3] or P[t+2]-2=P[t+1]), TS);
CROSSREFS
KEYWORD
nonn
AUTHOR
J. M. Bergot and Robert Israel, Mar 04 2020
STATUS
approved