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A139328 Sums of rows of the triangle in A139325. 2
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 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

a(n) = Sum(A139325(n,k): 1<=k<=n).

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},

..9 ..11 ..13 ..15 ... primes in 2nd row = {11,13},

.17 ..19 ..21 ..23 ... primes in 3rd row = {17,19},

.25 ..27 ..29 ..31 ... primes in 4th row = {29,31}.

CROSSREFS

Cf. A038107.

Sequence in context: A310069 A310070 A036572 * A253620 A282731 A134919

Adjacent sequences:  A139325 A139326 A139327 * A139329 A139330 A139331

KEYWORD

nonn

AUTHOR

Reinhard Zumkeller, Apr 14 2008

STATUS

approved

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Last modified August 14 21:07 EDT 2018. Contains 313756 sequences. (Running on oeis4.)