cp's OEIS Frontend

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.

%I A212123 #31 Jul 22 2012 17:22:03
%S A212123 1,3,4,7,8,10,14,16,19,20,25,29,32,34,35,41,46,50,53,55,56,63,68,71,
%T A212123 77,81,82,84,92
%N 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.
%C A212123 First differs from A213363 at a(12).
%F A212123 a(n) = A212124(n)/2.
%e A212123 Example 1: written as a triangle in which row i is related to the (i-1)st level of nucleus. Triangle begins:
%e A212123 1;
%e A212123 3,    4;
%e A212123 7,    8,  10;
%e A212123 14,  16,  19,  20;
%e A212123 25,  29,  32,  34,  35;
%e A212123 41,  46,  50,  53,  55,  56;
%e A212123 63,  68,  71,  77,  81,  82,  84;
%e A212123 ...
%e A212123 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:
%e A212123 1;
%e A212123 3,   4;
%e A212123 7,   8, 10;
%e A212123 14,
%e A212123 16, 19, 20, 25;
%e A212123 29, 32, 34, 35, 41;
%e A212123 46, 50, 53, 55, 56, 63;
%e A212123 68, 71, 77, 81, 82, 84, 92;
%e A212123 ...
%Y A212123 Partial sums of A212121. Other versions are A210983, A212013, A213363, A213373.
%Y A212123 Cf. A000292, A004006, A212122, A212124.
%K A212123 nonn,tabf,hard,more
%O A212123 1,2
%A A212123 _Omar E. Pol_, Jun 03 2012