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A130501 a(1)=1, a(n) = number of earlier terms of the sequence that divide (the sum of positive integers which are <=n and missing from first (n-1) terms of sequence). 1
1, 1, 2, 2, 4, 4, 2, 2, 6, 7, 6, 6, 2, 2, 10, 8, 2, 3, 2, 2, 12, 15, 14, 11, 14, 15, 5, 17, 16, 11, 3, 2, 14, 16, 2, 3, 17, 15, 4, 2, 16, 17, 3, 2, 19, 4, 22, 19, 6, 2, 16, 24, 5, 2, 40, 33, 22, 21, 26, 17, 13, 26, 3, 6, 22, 17, 2, 2, 23, 7, 25, 2, 29, 3, 27, 8, 23, 26, 9, 20 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

LINKS

Table of n, a(n) for n=1..80.

EXAMPLE

The positive integers which are <= 9 and are missing from the first 8 terms of the sequence are 3,5,6,7,8,9. The sum of these integers is 38, so a(9) is the number of earlier terms which divide 38. Therefore a(9) = 6.

MATHEMATICA

a = {1}; Do[AppendTo[a, Length[Select[a, Mod[(Plus @@ Complement[Range[n], a]), # ] == 0 &]]], {n, 2, 80}]; a (* Stefan Steinerberger, Dec 26 2007 *)

CROSSREFS

Cf. A130500.

Sequence in context: A071928 A325445 A165207 * A049116 A065176 A060267

Adjacent sequences:  A130498 A130499 A130500 * A130502 A130503 A130504

KEYWORD

nonn

AUTHOR

Leroy Quet, May 31 2007

EXTENSIONS

More terms from Stefan Steinerberger, Dec 26 2007

STATUS

approved

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Last modified June 21 10:09 EDT 2021. Contains 345360 sequences. (Running on oeis4.)