A154783 Row sums of triangle in A154720.

1, 6, 9, 20, 15, 30, 35, 40, 63, 70, 55, 108, 65, 70, 135, 112, 119, 162, 95, 140, 231, 198, 161, 312, 225, 182, 351, 196, 203, 450, 217, 352, 429, 238, 385, 540, 407, 418, 585, 440, 369, 798, 387, 396, 945, 414, 423, 720, 441, 650, 969, 676, 583, 1026, 825, 840

Offset: 1

Author

Omar E. Pol, Jan 15 2009

Keywords

• easy
• nonn

Comments

Also, row sums of triangle in A154722. - Omar E. Pol, Jan 16 2009

Crossrefs

Cf. A154720, A154721, A154722, A154784, A154785, A154786.

Programs

Maple

isA008578 := proc(n) RETURN(n=1 or isprime(n)) ; end: A154783 := proc(n) local a,d; a := n ; for d from 1 to n-1 do if isA008578(n-d) and isA008578(n+d) then a := a+2*n; fi; od: a ; end: for n from 1 to 80 do printf("%d,",A154783(n)) ; od: # R. J. Mathar, Jan 18 2009

Formula

a(n) = A154784(n) + n.

Extensions

Extended by R. J. Mathar, Jan 18 2009