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A132066 Irregular array: the sum of the first m terms of row n is the m-th positive divisor of n. 0
1, 1, 1, 1, 2, 1, 1, 2, 1, 4, 1, 1, 1, 3, 1, 6, 1, 1, 2, 4, 1, 2, 6, 1, 1, 3, 5, 1, 10, 1, 1, 1, 1, 2, 6, 1, 12, 1, 1, 5, 7, 1, 2, 2, 10, 1, 1, 2, 4, 8, 1, 16, 1, 1, 1, 3, 3, 9, 1, 18, 1, 1, 2, 1, 5, 10, 1, 2, 4, 14, 1, 1, 9, 11, 1, 22, 1, 1, 1, 1, 2, 2, 4, 12, 1, 4, 20, 1, 1, 11, 13, 1, 2, 6, 18, 1, 1, 2, 3 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,5

COMMENTS

Row n contains A000005(n) terms.

LINKS

Table of n, a(n) for n=1..99.

EXAMPLE

The positive divisors of 20 are 1,2,4,5,10,20. Row 20 of the array is 1,1,2,1,5,10. So we have 1=1; 1+1=2; 1+1+2=4; 1+1+2+1=5; 1+1+2+1+5=10; 1+1+2+1+5+10=20.

The first 10 rows:

1;

1,1;

1,2;

1,1,2;

1,4;

1,1,1,3

1,6;

1,1,2,4;

1,2,6;

1,1,3,5

MATHEMATICA

f[n_] := Block[{d}, d = Divisors[n]; d - Prepend[Most[d], 0]]; Flatten[Array[f, 40]] (* Ray Chandler, Nov 01 2007 *)

CROSSREFS

Cf. A027750, A000005.

Sequence in context: A033809 A046067 A305531 * A102190 A138650 A266685

Adjacent sequences:  A132063 A132064 A132065 * A132067 A132068 A132069

KEYWORD

nonn,tabf

AUTHOR

Leroy Quet, Oct 30 2007

EXTENSIONS

Extended by Ray Chandler, Nov 01 2007

STATUS

approved

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Last modified November 17 03:06 EST 2019. Contains 329216 sequences. (Running on oeis4.)