A080532 - OEIS

A080532

Number of nucleons in longest known radioactive decay series ending with Lead 209, reversed.

209, 209, 209, 213, 217, 221, 225, 225, 229, 233, 233, 237, 237, 241, 245, 249, 253, 257, 261, 265, 269, 273

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OFFSET

0,1

COMMENTS

The numbers are all == 1 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..21.

C. Heilman, The Pictorial Periodic Table

FORMULA

a(n)=A080536(n)+A080540(n).

CROSSREFS

Cf. A080529, A080530, A080531.

Sequence in context: A209300 A003740 A303688 * A153442 A159274 A330206

Adjacent sequences: A080529 A080530 A080531 * A080533 A080534 A080535

KEYWORD

nonn,hard

AUTHOR

Ralf Stephan, Feb 20 2003

STATUS

approved