

A226068


The sum of the positive integers not exceeding 2n that are representable as the sum of two successive sexy primes.


2



0, 0, 0, 0, 0, 0, 0, 16, 16, 36, 36, 36, 36, 64, 64, 96, 96, 96, 96, 136, 136, 136, 136, 136, 136, 188, 188, 188, 188, 188, 188, 188, 188, 256, 256, 256, 256, 256, 256, 336, 336, 336, 336, 424, 424, 424, 424, 424
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OFFSET

1,8


COMMENTS

4 divides a(n) for n > 0.


LINKS



FORMULA

a(n) = 2*Sum_{i=1..n} i * (pi(i3)  pi(i4)) * (pi(i+3)  pi(i+2)), where pi is the prime counting function (A000720).
a(n) = Sum_{i=1..2*n} c(i), where c is the characteristic function of A104010.  R. J. Mathar, May 28 2013


MAPLE

with(numtheory); A226068:=n>sum( 2*i*(pi(i3)  pi(i4)) * (pi(i+3)  pi(i+2)) , i = 1..n);


CROSSREFS



KEYWORD

nonn


AUTHOR



STATUS

approved



