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A259604
(A259542(n) + A259542(n+1)) / 2.
6
3, 6, 10, 15, 10, 6, 10, 15, 21, 28, 36, 45, 36, 28, 36, 45, 55, 36, 21, 28, 36, 45, 36, 28, 36, 45, 55, 66, 78, 91, 78, 66, 78, 91, 105, 78, 55, 66, 78, 91, 78, 66, 78, 91, 105, 120, 136, 153, 120, 78, 91, 105, 91, 78, 66, 78, 105, 120, 136, 153, 171, 153
OFFSET
1,1
COMMENTS
All terms are triangular numbers by definition of A259542.
LINKS
PROG
(Haskell)
a259604 n = a259604_list !! (n-1)
a259604_list = zipWith ((flip div 2 .) . (+))
a259542_list $ tail a259542_list
CROSSREFS
KEYWORD
nonn
AUTHOR
Reinhard Zumkeller, Jun 30 2015
STATUS
approved