OFFSET
1,1
FORMULA
a(n) = sqrt(A106573(n)).
EXAMPLE
a(2)=17 because the second square which is nor the sum nor the difference of two primes (289=17^2) is the 17th one in the succession of the perfect squares (thus: index 17).
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Alexandre Wajnberg, May 09 2005
EXTENSIONS
Corrected and extended by Ray Chandler, May 12 2005
STATUS
approved