A127460 - OEIS

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A127460

a(1)=1. a(n) = number of earlier terms a(k), 1<=k<=n-1, such that (k+a(k)) divides n.

1, 1, 1, 2, 0, 3, 0, 2, 2, 3, 1, 5, 1, 3, 2, 2, 3, 5, 0, 5, 2, 2, 2, 6, 3, 2, 2, 6, 1, 7, 0, 2, 2, 6, 3, 7, 1, 4, 2, 6, 1, 7, 1, 4, 3, 4, 0, 8, 2, 6, 5, 3, 0, 5, 3, 9, 2, 3, 2, 10, 2, 2, 4, 3, 3, 4, 2, 8, 4, 8, 0, 8, 1, 3, 4, 6, 3, 5, 1, 9, 2, 3, 2, 11, 6, 2, 2, 5, 2, 9, 4, 5, 3, 2, 4, 10, 1, 5, 5, 8, 0, 9, 1, 5

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,4

LINKS

Table of n, a(n) for n=1..104.

EXAMPLE

(a(1)+1) divides 10; (a(5)+5) divides 10; and (a(8)+8) divides 10. These 3 cases are the only cases where (a(k)+k) divides 10, for 1<=k<=9. So a(10)=3.

MATHEMATICA

f[l_List] := Block[{n = Length[l] + 1}, Append[l, Count[Table[Mod[n, k + l[[k]]], {k, n - 1}], 0]]]; Nest[f, {1}, 104] (* Ray Chandler, Jan 22 2007 *)

CROSSREFS

Cf. A127461, A127462.

Sequence in context: A325799 A355930 A229946 * A274021 A303711 A154109

Adjacent sequences: A127457 A127458 A127459 * A127461 A127462 A127463

KEYWORD

nonn

AUTHOR

Leroy Quet, Jan 15 2007

EXTENSIONS

Extended by Ray Chandler, Jan 22 2007

STATUS

approved