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Number of primes that are of the form n - 2^k - k^2.
0

%I #11 Mar 18 2014 01:10:56

%S 0,0,1,1,1,2,0,2,0,2,1,1,1,2,1,1,0,1,2,3,1,2,0,2,1,1,1,1,0,2,1,2,0,3,

%T 1,1,2,1,2,2,0,1,1,2,2,2,0,2,2,1,2,0,0,2,2,1,0,1,1,3,2,3,1,3,0,0,1,2,

%U 2,3,0,1,1,3,2,3,0,1,2,2,1,1,0,2,1,2,1,2,0,2

%N Number of primes that are of the form n - 2^k - k^2.

%C Indices of zeros in the sequence are 1, 2, 7, 9, 17, 23, 29, 33, 41, 47, 52, ...

%o (PARI) a(n)=sum(k=0,log(n)\log(2),isprime(n-2^k-k^2)) \\ _Charles R Greathouse IV_, Mar 18 2014

%K nonn,less

%O 1,6

%A _Irina Gerasimova_, Oct 26 2013

%E Terms corrected by _R. J. Mathar_, Oct 26 2013