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

20, 46, 160, 352, 940, 1822, 3670, 5284, 10510, 11800, 19192, 22678, 32590, 37060, 39430, 52222, 57868, 73180, 79834, 97690, 121522, 176830, 187084, 213964, 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

Offset: 1

Author

Cino Hilliard, Dec 03 2007

Keywords

• nonn

Comments

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

Programs

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
				

Formula

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

a(n) = A037074(n)+A001359(n+1). - R. J. Mathar, Sep 10 2016

Extensions

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