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 A087686 Elements of A004001 that repeat consecutively. 28
 1, 2, 4, 7, 8, 12, 14, 15, 16, 21, 24, 26, 27, 29, 30, 31, 32, 38, 42, 45, 47, 48, 51, 53, 54, 56, 57, 58, 60, 61, 62, 63, 64, 71, 76, 80, 83, 85, 86, 90, 93, 95, 96, 99, 101, 102, 104, 105, 106, 109, 111, 112, 114, 115, 116, 118, 119, 120, 121, 123, 124, 125, 126, 127 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS Complement of A088359; A051135(a(n)) > 1. [Reinhard Zumkeller, Jun 03 2011] From Antti Karttunen, Jan 18 2016: (Start) This set of numbers is closed with respect to A004001, see A266188. After 1, one more than the positions of zeros in A093879. (End) LINKS Reinhard Zumkeller, Table of n, a(n) for n = 1..10000 FORMULA Other identities. For all n >= 1: A080677(a(n)) = n. [See comments in A080677.] MATHEMATICA Conway[n_Integer?Positive] := Conway[n] =Conway[Conway[n-1]] + Conway[n - Conway[n-1]] Conway[1] = Conway[2] = 1 digits=1000 a=Table[Conway[n], {n, 1, digits}]; b=Table[If[a[[n]]-a[[n-1]]==0, a[[n]], 0], {n, 2, digits}]; c=Delete[Union[b], 1] PROG (Haskell) import Data.List (findIndices) a087686 n = a087686_list !! (n-1) a087686_list = map succ \$ findIndices (> 1) a051135_list -- Reinhard Zumkeller, Jun 03 2011 (Scheme, with Antti Karttunen's IntSeq-library) (define A087686 (MATCHING-POS 1 1 (lambda (n) (> (A051135 n) 1)))) ;; Antti Karttunen, Jan 18 2016 CROSSREFS Cf. A004001, A051135, A093879. Cf. A088359 (complement), A188163 (almost complement). Cf. A080677 (the least monotonic left inverse). Cf. also A266188, A265901, A265903, A267110, A267111, A267112. Sequence in context: A184414 A060406 A001839 * A232054 A216431 A233271 Adjacent sequences:  A087683 A087684 A087685 * A087687 A087688 A087689 KEYWORD nonn AUTHOR Roger L. Bagula, Sep 27 2003 STATUS approved

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Last modified May 12 07:28 EDT 2021. Contains 343821 sequences. (Running on oeis4.)