|
%I #16 Oct 11 2019 03:03:38
%S 4,10,16,22,28,30,36,40,48,52,56,58,70,78,84,90,100,102,110,128,132,
%T 134,146,154,164,176,208,252
%N Double magic numbers (in physics).
%C For the magic numbers see A018226.
%C 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.
%C 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.
%H Wikipedia, <a href="https://en.wikipedia.org/wiki/Magic_number_%28physics%29#Double_magic">Double magic</a>.
%H Wikipedia, <a href="https://en.wikipedia.org/wiki/List_of_nuclides">List of Nuclides</a>.
%F a(n) is the sum of two numbers from [2, 8, 20, 28, 50, 82, 126] (the magic numbers A018226).
%e 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.
%Y Cf. A018226, A033547.
%K nonn,fini
%O 1,1
%A _Wolfdieter Lang_, Dec 12 2012
|
