OFFSET
1,1
COMMENTS
A subsequence of A064238.
All terms are divisible by 30, and b(n)=a(n)/30 begins: 11, 51, 102, 142, 165, 228, 361, 513, 604, 767, 847, 868, 1059, 1110, 1337, 1383, 1502, 1661, 1796, 1978, 2195, ...
LINKS
Jon E. Schoenfield, Table of n, a(n) for n = 1..10000 (first 1000 terms from Giovanni Resta)
FORMULA
PROG
(Python)
import sympy
from sympy import isprime
for n in range(0, 100000, 2):
if isprime(n+1) and isprime(2*n+1) and isprime(3*n+1) and isprime(4*n+1):
print(str(n), end=', ')
CROSSREFS
KEYWORD
nonn
AUTHOR
Alex Ratushnyak, Feb 04 2014
STATUS
approved