OFFSET
1,2
LINKS
FORMULA
a(n) = A213374(n)/2.
EXAMPLE
Written as an irregular triangle in which row j is related to the j-th shell of nucleus. Note that row 4 has only one term. Triangle begins:
1;
3, 4;
7, 8, 10;
14;
16, 19, 20, 25;
29, 32, 38, 40, 41;
45, 50, 57, 59, 62, 63;
...
CROSSREFS
KEYWORD
nonn,tabf,hard,more
AUTHOR
Omar E. Pol, Jul 16 2012
STATUS
approved