OFFSET
1,3
COMMENTS
Related to the D_n Cartan like even groups that are like exceptional groups
MATHEMATICA
(*A123689*) a = {0, 2, 4, 10, 16, 26, 32, 46, 60, 74, 88, 108, 124, 146, 172, 194, 216, 248, 276, 308} Table[a[[n]]*(a[[n]] - 1)/2, {n, 1, Length[a]}]
CROSSREFS
KEYWORD
nonn,uned
AUTHOR
Roger L. Bagula, Aug 14 2007
STATUS
approved