%I #2 Mar 31 2012 20:55:21
%S 1,11,1,111,1,11,1111,11,1,111,11111,111,1,11,1111,111111,1111,11,1,
%T 111,11111,1111111,11111,111,1,11,1111,111111,11111111,111111,1111,11,
%U 1,111,11111,1111111
%N A model of the atomic nucleus (Shell model of nucleus). A triangle.
%C 1 is equal to 2 protons, 11 is equal to 2+2 protons, 111 is equal to 2+2+2 protons...
%C Repunit numbers represent the subshells.
%e A geometric model of the shell structure of nucleus:
%e ...|----------------------.i.----------------------|
%e ...|...|------------------.h.------------------|...|
%e ...|...|...|--------------.g.--------------|...|...|
%e ...|...|...|...|----------.f.----------|...|...|...|
%e ...|...|...|...|...|------.d.------|...|...|...|...|
%e ...|...|...|...|...|...|--.p.--|...|...|...|...|...|
%e ...|...|...|...|...|...|...s...|...|...|...|...|...|
%e ...|...|...|...|...|...|...|...|...|...|...|...|...|
%e ...|...|...|...|...|...|.......|...|...|...|...|...|
%e ...|...|...|...|...|.......1.......|...|...|...|...|
%e ...|...|...|...|......11.......1.......|...|...|...|
%e ...|...|...|......111......1......11.......|...|...|
%e ...|...|.....1111.....11.......1......111......|...|
%e ...|.....11111....111......1......11.....1111......|
%e ....111111...1111.....11.......1......111....11111....
%e 1111111..11111....111......1......11.....1111...111111
%e ......................................................
%e ...|...|...|...|...|...|...|...|...|...|...|...|...|
%e ...|...|...|...|...|...|...|1/2|...|...|...|...|...|
%e ...|...|...|...|...|...|----3/2----|...|...|...|...|
%e ...|...|...|...|...|--------5/2--------|...|...|...|
%e ...|...|...|...|------------7/2------------|...|...|
%e ...|...|...|----------------9/2----------------|...|
%e ...|...|-------------------11/2--------------------|
%e ...|----------------------.13/2.--------------------
%Y Cf. A056951, A130517, A130598, A130602.
%K nonn,tabl
%O 1,2
%A _Omar E. Pol_, Aug 09 2007, Aug 12 2007