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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 Reinhard Zumkeller, Table of n, a(n) for n = 1..500 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. Kevin Watkins, Abstract Interpretation Using Laziness: Proving Conway's Lost Cosmological Theorem, Kevin Watkins, Proving Conway's Lost Cosmological Theorem, POP seminar talk, CMU, Dec 2006 Eric Weisstein's World of Mathematics, Look and Say Sequence Wikipedia, 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 Cf. A119566, A213979. Sequence in context: A250493 A219322 A280349 * A053776 A217413 A217428 Adjacent sequences: A215400 A215401 A215402 * A215404 A215405 A215406 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.)