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Search: id:A128918
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A128918 a(n) = if n mod 2 == 1 then n*(n+1)/2 otherwise (n-1)*n/2 + 1. +0
2
1, 1, 2, 6, 7, 15, 16, 28, 29, 45, 46, 66, 67, 91, 92, 120, 121, 153, 154, 190, 191, 231, 232, 276, 277, 325, 326, 378, 379, 435, 436, 496, 497, 561, 562, 630, 631, 703, 704, 780, 781, 861, 862, 946, 947, 1035, 1036, 1128, 1129, 1225, 1226, 1326, 1327, 1431, 1432, 1540 (list; graph; listen)
OFFSET

0,3

CROSSREFS

Cf. A131179.

Sequence in context: A127406 A092310 A087376 this_sequence A078113 A030607 A049399

Adjacent sequences: A128915 A128916 A128917 this_sequence A128919 A128920 A128921

KEYWORD

nonn

AUTHOR

N. J. A. Sloane (njas(AT)research.att.com), Sep 26 2007

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Last modified December 2 11:54 EST 2009. Contains 167921 sequences.


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