OFFSET
1,1
COMMENTS
First terms absent in A064397: 2, 18, 28, 564, 1332, 3928, 12415, 13005, 16886.
EXAMPLE
2 is a term because prime(2) + prime(3) = 3 + 5 = 8 = 2^3 (perfect power);
7 is a term because prime(7) + prime(8) = 17 + 19 = 36 = 6^2 (perfect power);
39867 is a term because prime(39867) + prime(39868) = 478241 + 478243 = 956484 = 978^2 (perfect power).
PROG
(PARI) s=[]; for(n=1, 41530, a=prime(n)+prime(n+1); if(ispower(a), s=concat(s, n))); s
CROSSREFS
KEYWORD
nonn
AUTHOR
Zak Seidov, Nov 17 2007
STATUS
approved