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 A087836 a(n) = a(a(a(a(n-1)))) + a(n - a(n-1)) with a(1)=a(2)=1. 5
 1, 1, 2, 2, 3, 3, 3, 4, 4, 4, 4, 5, 5, 5, 5, 5, 6, 6, 6, 6, 6, 6, 7, 7, 7, 7, 7, 7, 7, 8, 8, 8, 8, 8, 8, 8, 8, 9, 9, 9, 9, 9, 9, 9, 9, 9, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 12, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 14, 14, 15 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,3 LINKS Joerg Arndt, Table of n, a(n) for n = 1..10000 MAPLE a:= proc(n) option remember; `if`(n<3, 1,       a(a(a(a(n-1)))) +a(n-a(n-1)))     end: seq(a(n), n=1..100);  # Alois P. Heinz, Aug 06 2017 MATHEMATICA a[n_Integer?Positive] := a[n] =a[a[a[a[n-1]]]] + a[n - a[n-1]]; a[1] = a[2] = 1; Table[a[n], {n, 1, 256}] PROG (PARI) lista(nn) = {va = vector(nn); va[1] = 1; va[2] = 1; for (n=3, nn, va[n] = va[va[va[va[n-1]]]]+va[n-va[n-1]]; ); va; } \\ Michel Marcus, Aug 06 2017 CROSSREFS Cf. A004001. Different from A087817. Sequence in context: A107436 A002024 A123578 * A087845 A130146 A113764 Adjacent sequences:  A087833 A087834 A087835 * A087837 A087838 A087839 KEYWORD nonn AUTHOR Roger L. Bagula, Oct 07 2003 EXTENSIONS Corrected by Michel Marcus, Aug 06 2017 STATUS approved

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Last modified April 6 12:19 EDT 2020. Contains 333273 sequences. (Running on oeis4.)