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A210983 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. 7
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 (list; graph; refs; listen; history; text; internal format)
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?

A: The order of A212121 is defined by A212122.

Note that there are at least five versions of the nuclear shell model in the OEIS:

Goeppert-Mayer (1950): A212012, A004736, A212013, A212014.

Goeppert-Mayer, Jensen (1955): A212122, A212121, A212123, A212124.

Talmi (1993): A213362, A213361, A213363, A213364.

Meyerhof: A213372, A213371, A213373, A213374.

For another version: A162630, A130517, A210983, A210984.

Each version is represented by four sequences: the first sequence is the main entry.

(End)

For additional information see A162630.

LINKS

Table of n, a(n) for n=1..56.

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;

...

Column 1 gives positive terms of A004006. Right border gives positives terms of A000292.

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

Partial sums of A130517 (when that sequence is regarded as a flattened triangle). Other versions are A212013, A212123, A213363, A213373.

Cf. A000292, A004006, A162630, A210984

Sequence in context: A189750 A153144 A032788 * A213363 A212123 A213373

Adjacent sequences:  A210980 A210981 A210982 * A210984 A210985 A210986

KEYWORD

nonn,tabf

AUTHOR

Omar E. Pol, Jul 14 2012

STATUS

approved

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Last modified September 28 17:43 EDT 2020. Contains 337393 sequences. (Running on oeis4.)