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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 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.)