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A120615 a(n)=sum(k=0,n,floor(phi*floor(n/phi))) where phi=(1+sqrt(5))/2. 2
0, 1, 2, 5, 9, 13, 19, 25, 33, 42, 51, 62, 74, 86, 100, 114, 130, 147, 164, 183, 202, 223, 245, 267, 291, 316, 341, 368, 395, 424, 454, 484, 516, 549, 582, 617, 652, 689, 727, 765, 805, 845, 887, 930, 973, 1018, 1064, 1110, 1158, 1206, 1256, 1307, 1358, 1411 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

LINKS

Table of n, a(n) for n=1..54.

FORMULA

a(n)=n*(n-3)/2+ceil(n/phi)

PROG

(PARI) phi=(1+sqrt(5))/2; a(n)=n*(n-3)/2+ceil(n/phi)

CROSSREFS

Cf. A120613, A120614.

Sequence in context: A219647 A129726 A122489 * A038707 A290140 A071705

Adjacent sequences:  A120612 A120613 A120614 * A120616 A120617 A120618

KEYWORD

nonn

AUTHOR

Benoit Cloitre, Jun 17 2006

STATUS

approved

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Last modified July 22 03:22 EDT 2017. Contains 289648 sequences.