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 A135283 Sum of staircase twin primes according to the rule: top + bottom + next top. 3
 13, 23, 41, 65, 101, 143, 191, 245, 311, 353, 425, 479, 551, 581, 623, 695, 749, 821, 875, 971, 1115, 1271, 1325, 1445, 1613, 1739, 1817, 1877, 1943, 2129, 2441, 2471, 2513, 2597, 2783, 3071, 3113, 3161, 3215, 3335, 3533, 3737, 3845, 3881, 3923, 4067 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS We list the twin primes in staircase fashion as follows. 3 5_5 __7_11 ____13_17 _______19_29 __________31_41 _____________.._.. ________________tu(n)_tl(n) ______________________tu(n+1) ... where tl(n) = n-th lower twin prime, tu(n) = n-th upper twin prime. Then a(n) = tl(n) + tu(n) + tl(n+1). LINKS FORMULA a(n) = A054735(n)+A001359(n+1). - R. J. Mathar, Sep 10 2016 PROG (PARI) g(n) = for(x=1, n, y=twinu(x)+twinl(x) + twinl(x+1); print1(y", ")) twinl(n) = / *The n-th lower twin prime. */ { local(c, x); c=0; x=1; while(c

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Last modified November 28 03:39 EST 2022. Contains 358406 sequences. (Running on oeis4.)