OFFSET
1,1
COMMENTS
Corresponding squares a(n)+prime(n): 9,16,16,36,64,36,36,576,64,100.
Also, a(n) >= A157480(n).
LINKS
Zak Seidov, Table of n, a(n) for n = 1..10000
MATHEMATICA
Table[p=Prime[n]; x=1+Floor[Sqrt[2*p]]; While[!PrimeQ[q=x^2-p], x++]; q, {n, 100}]
PROG
(PARI) a(n)=p = prime(n); k = nextprime(p+1); while(!issquare(p+k), k = nextprime(k+1)); k; \\ Michel Marcus, Jun 22 2015
(PARI) a(n, p=prime(n))=my(s=sqrtint(2*p)); while(!isprime(s++^2-p), ); s^2-p \\ Charles R Greathouse IV, May 06 2016
CROSSREFS
KEYWORD
nonn
AUTHOR
Zak Seidov, Jun 22 2015
STATUS
approved