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A080530 Number of nucleons in longest known radioactive decay series ending with Lead 207 ("actinium series"), reversed. 5
207, 207, 211, 211, 215, 215, 219, 223, 227, 227, 231, 235, 239, 243, 247, 251, 255, 259, 263, 267, 271 (list; graph; refs; listen; history; text; internal format)
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
FORMULA
a(n)=A080534(n)+A080538(n).
CROSSREFS
Sequence in context: A285754 A201032 A133149 * A192825 A045069 A199497
KEYWORD
nonn,hard
AUTHOR
Ralf Stephan, Feb 20 2003
STATUS
approved

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Last modified June 18 13:40 EDT 2024. Contains 373481 sequences. (Running on oeis4.)