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 A309072 a(n) is the concatenation of the initial digit of A247476(k) for k = A309063(n)..A309063(n+1)-1. 2
 12132453674859161724822942, 121121, 121121, 2342536434553643455364345536436553789651617788966917178682392737988131273298, 78912142738493, 912112112192, 121121, 121121, 121121, 121121, 121121, 121121, 121121, 121121, 121121, 121121, 121121, 121121, 121121 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS For any n > 0: - a(n) has an even number of digits, - for any digit d appearing in a(n): - d appears an even number of times, - each pair of digits d is separated by d other digits, - a(n) cannot be split into two parts with these properties. The distribution of the first million values is as follows: Freq. Length Value ------ ------- -------------------------------------------------------------- 932062 6 121121 44451 38 78912142778498923727318198971711218297 19557 12 891211211819 3915 12 912112112192 3 14 78912142738493 1 26 12132453674859161724822942 1 76 234253643455364345536434553643..966917178682392737988131273298 1 280 789121427784989237213188991211..392931211212392931211212392131 1 712 121322432234223322432234223322..819191717881219277988131273298 1 2200 789121427784989237213188991211..392931211212392931211212392131 1 6438 121322432234223322432234223322..798916167718196687792562387539 1 64958 121322432234223322432234223322..819191717881219277988131273298 1 112810 678912162768798916167718196687..687989161677181968971711218297 1 563478 121322432234223322432234223322..177669883476364987896612172869 1 744654 678912162768798916167718196687..819191717881219277988131273298 1 2095732 789121427784989237273181989712..392931211212392931211212392131 1 5830936 234253243252332243223422332243..177669883476364987896612172869 LINKS Table of n, a(n) for n=1..19. Rémy Sigrist, C program for A309072 EXAMPLE For n = 2: - A309063(2) = 27 and A309063(3)-1 = 32, - A000030(A247476(27)) = A000030(13) = 1, - A000030(A247476(28)) = A000030(25) = 2, - A000030(A247476(29)) = A000030(14) = 1, - A000030(A247476(30)) = A000030(15) = 1, - A000030(A247476(31)) = A000030(26) = 2, - A000030(A247476(32)) = A000030(16) = 1, - hence a(2) = 121121. PROG (C) See Links section. CROSSREFS Cf. A000030, A247476, A309063. Sequence in context: A280347 A009190 A095444 * A217416 A358418 A133849 Adjacent sequences: A309069 A309070 A309071 * A309073 A309074 A309075 KEYWORD nonn,base AUTHOR Rémy Sigrist, Jul 10 2019 STATUS approved

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Last modified May 28 05:47 EDT 2024. Contains 372902 sequences. (Running on oeis4.)