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A212123
Total number of pairs of states of the first n subshells of the nuclear shell model in which the subshells are ordered by energy level in increasing order.
8
1, 3, 4, 7, 8, 10, 14, 16, 19, 20, 25, 29, 32, 34, 35, 41, 46, 50, 53, 55, 56, 63, 68, 71, 77, 81, 82, 84, 92
OFFSET
1,2
COMMENTS
First differs from A213363 at a(12).
FORMULA
a(n) = A212124(n)/2.
EXAMPLE
Example 1: written as a triangle in which row i is related to the (i-1)st level of nucleus. Triangle begins:
1;
3, 4;
7, 8, 10;
14, 16, 19, 20;
25, 29, 32, 34, 35;
41, 46, 50, 53, 55, 56;
63, 68, 71, 77, 81, 82, 84;
...
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, 19, 20, 25;
29, 32, 34, 35, 41;
46, 50, 53, 55, 56, 63;
68, 71, 77, 81, 82, 84, 92;
...
CROSSREFS
Partial sums of A212121. Other versions are A210983, A212013, A213363, A213373.
Sequence in context: A338733 A210983 A213363 * A213373 A363353 A332059
KEYWORD
nonn,tabf,hard,more
AUTHOR
Omar E. Pol, Jun 03 2012
STATUS
approved