OFFSET
1,2
COMMENTS
Additional comments from Omar E. Pol, Sep 02 2012: (Start)
Q: What are energy levels?
A: See the link sections of A212122, A213362, A213372. For example, see this link related to A213372: http://www.flickr.com/photos/mitopencourseware/3772864128/in/set-72157621892931990
Q: What defines the order in A212121?
Note that there are at least five versions of the nuclear shell model in the OEIS:
Each version is represented by four sequences: the first sequence is the main entry.
(End)
For additional information see A162630.
FORMULA
a(n) = A210984(n)/2.
EXAMPLE
Example 1: written as a triangle in which row i is related to the (i-1)st level of nucleus, the sequence begins:
1;
3, 4;
7, 8, 10;
14, 16, 17, 20;
25, 28, 29, 31, 35;
41, 45, 47, 48, 51, 56;
63, 68, 71, 72, 74, 78, 84;
92, 98, 102, 104, 105, 108, 113, 120;
129, 136, 141, 144, 145, 147, 151, 157, 165;
175, 183, 189, 193, 195, 196, 199, 204, 211, 220;
...
Example 2: written as an irregular triangle in which row j is related to the j-th shell of nucleus. Note that in this case row 4 has only one term. Triangle begins:
1;
3, 4;
7, 8, 10;
14;
16, 17, 20, 25;
28, 29, 31, 35, 41;
45, 47, 48, 51, 56, 63;
68, 71, 72, 74, 78, 84, 92;
98, 102, 104, 105, 108, 113, 120, 129;
136, 141, 144, 145, 147, 151, 157, 165, 175;
183, 189, 193, 195, 196, 199, 204, 211, 220, 231;
...
CROSSREFS
KEYWORD
nonn,tabf
AUTHOR
Omar E. Pol, Jul 14 2012
STATUS
approved