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 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 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,8 COMMENTS 4 divides a(n) for n > 0. LINKS Table of n, a(n) for n=1..48. FORMULA a(n) = 2*Sum_{i=1..n} i * (pi(i-3) - pi(i-4)) * (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(i-3) - pi(i-4)) * (pi(i+3) - pi(i+2)) , i = 1..n); seq(A226068(k), k = 1..70); CROSSREFS Cf. A000720, A104010, A098428. Sequence in context: A040241 A278348 A022350 * A087970 A230977 A174683 Adjacent sequences: A226065 A226066 A226067 * A226069 A226070 A226071 KEYWORD nonn AUTHOR Wesley Ivan Hurt, May 24 2013 STATUS approved

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Last modified May 30 14:11 EDT 2023. Contains 363055 sequences. (Running on oeis4.)