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A215403 Isotopes of Conway's audioactive transuranic elements, in reversed lexicographic order. 3
312211322212221121123222114, 13112221133211322112211213322114, 312211322212221121123222115, 13112221133211322112211213322115, 312211322212221121123222116, 13112221133211322112211213322116, 312211322212221121123222117, 13112221133211322112211213322117 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
COMMENTS
The transuranic elements Pu=31221132221222112112322211 and Np=1311222113321132211221121332211 are alternating prefixes;
n is suffix of a(2*n - 1) and of a(2*n) in decimal representation.
LINKS
J. H. Conway, The weird and wonderful chemistry of audioactive decay, in T. M. Cover and Gopinath, eds., Open Problems in Communication and Computation, Springer, NY 1987, pp. 173-188.
Eric Weisstein's World of Mathematics, Look and Say Sequence
PROG
(Haskell)
a215403 n k = a215403_list !! (n-1)
a215403_list = map (foldr (\d v -> 10 * v + d) 0) $
concatMap (\x -> map (x :) [plut', nept']) [4..] where
plut' = [1, 1, 2, 2, 2, 3, 2, 1, 1, 2, 1, 1, 2, 2, 2, 1, 2, 2, 2, 3, 1, 1, 2, 2, 1, 3]
nept' = [1, 1, 2, 2, 3, 3, 1, 2, 1, 1, 2, 2, 1, 1, 2, 2, 3, 1, 1, 2, 3, 3, 1, 1, 2, 2, 2, 1, 1, 3, 1]
CROSSREFS
Sequence in context: A250493 A219322 A280349 * A053776 A217413 A217428
KEYWORD
nonn,base
AUTHOR
Reinhard Zumkeller, Aug 09 2012
STATUS
approved

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Last modified May 30 17:43 EDT 2024. Contains 372971 sequences. (Running on oeis4.)