A080530 Number of nucleons in longest known radioactive decay series ending with Lead 207 ("actinium series"), reversed.

207, 207, 211, 211, 215, 215, 219, 223, 227, 227, 231, 235, 239, 243, 247, 251, 255, 259, 263, 267, 271

Offset

0,1

Comments

The numbers are all equivalent to 3 mod 4. The sequence was submitted reversed, as it is open in the past. It is unknown if reversed decay series are finite (the "island of stability" hypothesis).

Links

Table of n, a(n) for n=0..20.

C. Heilman, The Pictorial Periodic Table

Formula

a(n)=A080534(n)+A080538(n).

Crossrefs

Cf. A080529, A080531, A080532.

Sequence in context: A285754 A201032 A133149 * A192825 A045069 A199497

Adjacent sequences: A080527 A080528 A080529 * A080531 A080532 A080533

Keyword

nonn,hard

Author

Ralf Stephan, Feb 20 2003

Status

approved