A154786 Row sums of triangle in A154725.

0, 0, 0, 8, 10, 12, 14, 32, 36, 40, 44, 72, 52, 56, 90, 64, 102, 144, 38, 120, 168, 132, 138, 240, 200, 156, 270, 168, 174, 360, 124, 320, 396, 136, 350, 432, 296, 380, 546, 320, 328, 672, 344, 352, 810, 368, 376, 672, 294, 600, 816, 520, 530, 864, 660, 784, 1140

Offset: 1

Author

Omar E. Pol, Jan 15 2009, Jan 16 2009

Keywords

• easy
• nonn

Crossrefs

Cf. A154724, A154725, A154726, A154727, A154783, A154784, A154785.

Cf. A005843, A061357, A154720, A154787. - Omar E. Pol, Jan 20 2009

Programs

Maple

A154786 := proc(n) local a,d; a := 0 ; for d from 1 to n-2 do if isprime(n-d) and isprime(n+d) then a := a+2*n; fi; od: a ; end: for n from 1 to 80 do printf("%d,",A154786(n)) ; od: # R. J. Mathar, Jan 18 2009

Formula

a(n) = A154785(n) - n.

a(n) = A005843(n)*A061357(n). - Omar E. Pol, Jan 20 2009

Extensions

Edited by Omar E. Pol, Jan 17 2009

Extended by R. J. Mathar, Jan 18 2009