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A023863
a(n) = 1*t(n) + 2*t(n-1) + ... + k*t(n+1-k), where k=floor((n+1)/2) and t = A002808 (composite numbers).
0
4, 6, 20, 25, 52, 59, 104, 119, 186, 211, 306, 338, 464, 502, 663, 715, 914, 981, 1222, 1297, 1585, 1667, 2004, 2104, 2494, 2615, 3062, 3191, 3700, 3854, 4429, 4610, 5256, 5466, 6186, 6426, 7224, 7477, 8356, 8620, 9582, 9878, 10929, 11261, 12405, 12774, 14014, 14422
OFFSET
1,1
CROSSREFS
Sequence in context: A354204 A123169 A205955 * A024480 A066193 A026711
KEYWORD
nonn
EXTENSIONS
Title simplified by Sean A. Irvine, Jun 12 2019
STATUS
approved