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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 (list; graph; refs; listen; history; text; internal format)
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

Tin-132 is a double magic radionuclide (unstable isotope) with nucleon number A = 132 = a(21), Z = 50 and N = 82. Similarly for tin-100 with Z = N = 50. The stable primordial nuclide barium-132 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

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Last modified January 27 10:50 EST 2021. Contains 340465 sequences. (Running on oeis4.)