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A130556 A model of the atomic nucleus (Shell model of nucleus). A triangle. 11
1, 11, 1, 111, 1, 11, 1111, 11, 1, 111, 11111, 111, 1, 11, 1111, 111111, 1111, 11, 1, 111, 11111, 1111111, 11111, 111, 1, 11, 1111, 111111, 11111111, 111111, 1111, 11, 1, 111, 11111, 1111111 (list; table; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

1 is equal to 2 protons, 11 is equal to 2+2 protons, 111 is equal to 2+2+2 protons...

Repunit numbers represent the subshells.

LINKS

Table of n, a(n) for n=1..36.

EXAMPLE

A geometric model of the shell structure of nucleus:

...|----------------------.i.----------------------|

...|...|------------------.h.------------------|...|

...|...|...|--------------.g.--------------|...|...|

...|...|...|...|----------.f.----------|...|...|...|

...|...|...|...|...|------.d.------|...|...|...|...|

...|...|...|...|...|...|--.p.--|...|...|...|...|...|

...|...|...|...|...|...|...s...|...|...|...|...|...|

...|...|...|...|...|...|...|...|...|...|...|...|...|

...|...|...|...|...|...|.......|...|...|...|...|...|

...|...|...|...|...|.......1.......|...|...|...|...|

...|...|...|...|......11.......1.......|...|...|...|

...|...|...|......111......1......11.......|...|...|

...|...|.....1111.....11.......1......111......|...|

...|.....11111....111......1......11.....1111......|

....111111...1111.....11.......1......111....11111....

1111111..11111....111......1......11.....1111...111111

......................................................

...|...|...|...|...|...|...|...|...|...|...|...|...|

...|...|...|...|...|...|...|1/2|...|...|...|...|...|

...|...|...|...|...|...|----3/2----|...|...|...|...|

...|...|...|...|...|--------5/2--------|...|...|...|

...|...|...|...|------------7/2------------|...|...|

...|...|...|----------------9/2----------------|...|

...|...|-------------------11/2--------------------|

...|----------------------.13/2.--------------------

CROSSREFS

Cf. A056951, A130517, A130598, A130602.

Sequence in context: A104490 A164851 A038713 * A277932 A290676 A290420

Adjacent sequences:  A130553 A130554 A130555 * A130557 A130558 A130559

KEYWORD

nonn,tabl

AUTHOR

Omar E. Pol, Aug 09 2007, Aug 12 2007

STATUS

approved

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Last modified May 27 03:03 EDT 2020. Contains 334647 sequences. (Running on oeis4.)