A139328 - OEIS

A139328

Sums of rows of the triangle in A139325.

0, 3, 6, 10, 14, 19, 24, 30, 36, 45, 52, 60, 67, 76, 86, 96, 105, 117, 127, 138, 151, 162, 176, 189, 203, 216, 230, 246, 262, 277, 292, 308, 325, 343, 362, 376, 398, 417, 435, 451, 473, 491, 515, 535, 557, 579, 599, 622, 646, 668, 691, 712, 737, 764, 788, 815

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OFFSET

1,2

COMMENTS

a(n) = Sum_{k=1..n} A139325(n,k).

LINKS

Table of n, a(n) for n=1..56.

FORMULA

a(n) = A000720(2*n^2 - 1) - 1.

EXAMPLE

a(4) = #{3,5,7}+#{11,13}+#{17,19,23}+#{29,31} = 3+2+3+2 = 10:

..1 ...3 ...5 ...7 ... primes in first row = {3,5,7},