OFFSET
1,2
COMMENTS
The number 2 appears only in column 1 of A217916 (when treated as a triangle).
FORMULA
Involves triangular-indexed twin primes:
prime(a(n)*(a(n)-1)/2 + 1) - prime(a(n)*(a(n)-1)/2) = 2 for n>1 with a(1)=1.
CROSSREFS
KEYWORD
nonn
AUTHOR
Paul D. Hanna, Mar 04 2013
STATUS
approved