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A157512 Partial sums of A157502. 2
2, 8, 16, 26, 38, 52, 70, 90, 112, 136, 162, 190, 220, 252, 286, 324, 364, 406, 450, 496, 544, 594, 646, 700, 756, 814, 874, 936, 1002, 1070, 1140, 1212, 1286, 1362, 1440, 1520, 1602, 1686, 1772, 1860, 1950, 2042, 2136, 2232, 2330, 2432, 2536 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..47.

FORMULA

Set R(n) = floor(A157502(n)/2) and S(n) = floor(sqrt(A157502(n))/2); then a(n) = R(n)*(R(n) + 1) - (4*S(n)^3 + 6*S(n)^2 + 2*S(n))/3.

EXAMPLE

a(4) = 2 + 6 + 8 + 10 = 26.

PROG

(PARI) lista(nn) = {s = 0; forstep (i = 2, nn, 2, if (! issquare(i), s+=i; print1(s, ", "); ); ); } \\ Michel Marcus, Aug 26 2013

CROSSREFS

Cf. A157502.

Sequence in context: A169925 A225289 A322945 * A252594 A137882 A194643

Adjacent sequences:  A157509 A157510 A157511 * A157513 A157514 A157515

KEYWORD

nonn

AUTHOR

Gerald Hillier, Mar 02 2009

EXTENSIONS

More terms from Michel Marcus, Aug 26 2013

STATUS

approved

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Last modified August 9 02:14 EDT 2020. Contains 336310 sequences. (Running on oeis4.)