A087836 - OEIS

A087836

a(n) = a(a(a(a(n-1)))) + a(n - a(n-1)) with a(1)=a(2)=1.

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