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).

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

Links

Table of n, a(n) for n=1..48.

Crossrefs

Sequence in context: A354204 A123169 A205955 * A024480 A066193 A026711

Adjacent sequences: A023860 A023861 A023862 * A023864 A023865 A023866

Keyword

nonn

Author

Clark Kimberling

Extensions

Title simplified by Sean A. Irvine, Jun 12 2019

Status

approved