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A127417 a(1)=1; for n > 1, a(n) = number of earlier terms a(k), 1<k<=n-1, such that (a(k)+n) is divisible by k. 1
1, 1, 2, 2, 2, 2, 3, 2, 2, 4, 3, 1, 4, 3, 2, 5, 2, 4, 4, 1, 2, 6, 4, 1, 6, 3, 3, 5, 2, 4, 3, 4, 3, 6, 4, 2, 3, 5, 5, 4, 3, 3, 7, 2, 2, 7, 4, 3, 5, 3, 4, 5, 6, 3, 3, 4, 2, 6, 6, 4, 6, 4, 5, 3, 3, 5, 5, 3, 3, 7, 6, 2, 6, 5, 4, 5, 2, 5, 8, 1, 5, 6, 5, 1, 6, 7, 3, 9, 2, 4, 5, 2, 5, 6, 6, 5, 5, 4, 4, 6, 4, 4, 6, 3, 4 (list; graph; refs; listen; history; internal format)
OFFSET

1,3

COMMENTS

The value of a(1) = 1 is arbitrary. a(1) can be any integer and the rest of the sequence would remain unchanged.

EXAMPLE

a(1)+11 = 12 is a multiple of 1; a(2)+11 = 12 is a multiple of 2; and a(7)+11 = 14 is a multiple of 7. These 3 are the only cases where (a(k)+11) is a multiple of k, for 1 <=k <=10. So a(11) = 3.

MATHEMATICA

f[l_List] := Block[{n = Length[l] + 1}, Append[l, Count[Table[Mod[l[[k]] + n, k], {k, n - 1}], 0]]]; Nest[f, {1}, 105] (*Chandler*)

CROSSREFS

Cf. A127418.

Sequence in context: A067595 A184721 A134868 * A198897 A201375 A128764

Adjacent sequences:  A127414 A127415 A127416 * A127418 A127419 A127420

KEYWORD

nonn

AUTHOR

Leroy Quet Jan 13 2007

EXTENSIONS

Extended by Ray Chandler (rayjchandler(AT)sbcglobal.net), Jan 22 2007

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Last modified February 14 23:43 EST 2012. Contains 205689 sequences.