

A219239


Double magic numbers (in physics).


0



4, 10, 16, 22, 28, 30, 36, 40, 48, 52, 56, 58, 70, 78, 84, 90, 100, 102, 110, 128, 132, 134, 146, 154, 164, 176, 208, 252
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OFFSET

1,1


COMMENTS

For the magic numbers see A018226.
An atomic nucleus is called double magic if Z (number of protons in an atomic nucleus, atomic number) and N (number of neutrons) are both magic numbers. The nucleon or mass number (forget the Z electrons) is A = Z + N.
Each number a(n) is obtained in only one way as a sum of two (possibly equal) magic numbers. Only 28 is magic and double magic.


LINKS

Table of n, a(n) for n=1..28.
Wikipedia, Double magic.
Wikipedia, List of Nuclides.


FORMULA

a(n) is the sum of two numbers from [2, 8, 20, 28, 50, 82, 126] (the magic numbers A018226).


EXAMPLE

Tin132 is a double magic radionuclide (unstable isotope) with nucleon number A = 132 = a(21), Z = 50 and N = 82. Similarly for tin100 with Z = N = 50. The stable primordial nuclide barium132 is not double magic, because it has Z = 56 and N = 76.


CROSSREFS

Cf. A018226, A033547.
Sequence in context: A310523 A310524 A140493 * A141427 A310525 A310526
Adjacent sequences: A219236 A219237 A219238 * A219240 A219241 A219242


KEYWORD

nonn,fini


AUTHOR

Wolfdieter Lang, Dec 12 2012


STATUS

approved



