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 A135286 Sum of staircase twin primes according to the rule: top * bottom + next top. 0

%I

%S 20,46,160,352,940,1822,3670,5284,10510,11800,19192,22678,32590,37060,

%T 39430,52222,57868,73180,79834,97690,121522,176830,187084,213964,

%U 273052,325498,360616,382564,412822,436408,656920,676510,686440,737044,778942,1041430,1066072,1103560,1128934,1193614,1328332,1514176,1634572,1665400,1696522,1743826,2040634,2109784,2197810,2215750

%N Sum of staircase twin primes according to the rule: top * bottom + next top.

%C While there is multiplication in the generation of this sequence, it is still called a sum because the arithmetic processes -,*,/ are derived from addition.

%F We list the twin primes in staircase fashion as in A135283. Then a(n) = tl(n) * tu(n) + tl(n+1).

%F a(n) = A037074(n)+A001359(n+1). - _R. J. Mathar_, Sep 10 2016

%o (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<n, if(ispseudoprime(prime(x)+2),c++); x++; ); return(prime(x-1)) } twinu(n) = /* The n-th upper twin prime. */ { local(c,x); c=0; x=1; while(c<n, if(isprime(prime(x)+2),c++); x++; ); return(prime(x)) }

%K nonn

%O 1,1

%A _Cino Hilliard_, Dec 03 2007

%E All the entries were wrong. They have been corrected by Franklin T. Adams-Watters, Apr 29 2008

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Last modified September 23 10:55 EDT 2021. Contains 347612 sequences. (Running on oeis4.)