OFFSET
1,1
COMMENTS
p + (p^2-1)/6 is the square of a prime for primes p = 5, 29 and 73. Are there any others?
LINKS
Robert Israel, Table of n, a(n) for n = 1..15
EXAMPLE
a(3)=73 is a term because 73 is prime and 73+(73^2-1)/6 = 961 = 31^2 is a square.
MAPLE
f:= gfun:-rectoproc({a(i+4)-10*a(i+2)+a(i)=24, a(0)=1, a(1)=1, a(2)=5, a(3)=29}, a(i), remember):
select(isprime, map(f, [$1..100]));
CROSSREFS
KEYWORD
nonn
AUTHOR
J. M. Bergot and Robert Israel, Dec 23 2020
STATUS
approved