login

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).

A212287
Primes of the form m*p^2 + 1, where p is prime and m <= p^2.
1
5, 13, 17, 19, 37, 73, 101, 151, 197, 251, 401, 491, 601, 677, 727, 883, 1373, 1453, 1471, 1667, 2029, 2179, 2663, 3389, 3469, 3631, 3719, 4057, 4357, 4733, 5477, 6359, 6761, 7019, 8093, 8713, 8837, 9127, 9439, 9803, 9923, 10093, 10141, 10831, 10891, 11617, 11831, 12101, 12343
OFFSET
1,1
COMMENTS
Not known to be infinite, but see the Matomäki link.
LINKS
Charles R Greathouse IV, Table of n, a(n) for n = 1..10000
Kaisa Matomäki, A note on primes of the form p = aq^2 + 1, Acta Arith. 137 (2009), pp. 133-137.
EXAMPLE
13 is a member since 13 = 3 * 2^2 + 1 with 3 <= 2^2 and 3 is prime.
PROG
(PARI) list(lim)=my(v=List(), t); lim=lim\1-.5; forprime(p=2, sqrt(lim), for(a=1, min(lim\p^2, p^2), if(isprime(t=a*p^2+1), listput(v, t)))); vecsort(Vec(v), , 8)
CROSSREFS
Sequence in context: A049092 A103666 A082700 * A174361 A226165 A166409
KEYWORD
nonn
AUTHOR
STATUS
approved