A318998 Number of stable nuclides with neutron number n.

1, 2, 1, 1, 1, 2, 2, 2, 2, 1, 3, 1, 3, 1, 3, 1, 3, 1, 3, 0, 5, 1, 3, 1, 3, 1, 3, 2, 5, 1, 4, 1, 3, 1, 3, 0, 3, 1, 3, 0, 4, 1, 4, 1, 4, 0, 4, 1, 4, 1, 6, 1, 4, 1, 3, 2, 4, 1, 5, 1, 4, 0, 4, 1, 4, 2, 3, 1, 3, 1, 4, 1, 4, 1, 5, 1, 3, 1, 5, 1, 3, 2, 7, 1, 2, 2, 2

Offset

0,2

Comments

Radioactive nuclides with a half-life of 700 million years or greater (i.e., half-life longer than or equal to that of uranium-235) are included.

The last known term is a(177) = 0.

Sum_{n=0..177} a(n) = 286, which is the number of known stable nuclides.

For n <= 126, a(n) = 0 for n = 19, 35, 39, 45, 61, 89, 115, 123.

The total number of stable nuclides with an even neutron number is 220, while for odd neutron number it's 66.

The number of even numbers k such that a(k) = 1, 2, 3, 4, 5, 6, 7 are 5, 6, 28, 19, 6, 1, 1. There are 46 odd numbers such that a(k) = 1 and only 10 such that a(k) = 2.

Links

Jianing Song, Table of n, a(n) for n = 0..177

Wikipedia, Table of nuclides.

Wikipedia, Neutron number.

Wikipedia, Isotone.

Example

Stable nuclides with neutron number n:
n = 20: sulfur-36, chlorine-37, argon-38, potassium-39, calcium-40;
n = 50: krypton-86, rubidium-87, strontium-88, yttrium-89, zirconium-90, molybdenum-92;
n = 85: neodymium-145, samarium-147.

Crossrefs

Cf. A179301 (proton number), A318997 (mass number), A318999 (neutron excess).

Sequence in context: A273190 A086288 A104360 * A079951 A095407 A038605

Adjacent sequences: A318995 A318996 A318997 * A318999 A319000 A319001

Keyword

nonn

Author

Jianing Song, Sep 07 2018

Status

approved