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A179942 Number of times n appears in a 1000 x 1000 multiplication table. 3
1, 2, 2, 3, 2, 4, 2, 4, 3, 4, 2, 6, 2, 4, 4, 5, 2, 6, 2, 6, 4, 4, 2, 8, 3, 4, 4, 6, 2, 8, 2, 6, 4, 4, 4, 9, 2, 4, 4, 8, 2, 8, 2, 6, 6, 4, 2, 10, 3, 6, 4, 6, 2, 8, 4, 8, 4, 4, 2, 12, 2, 4, 6, 7, 4, 8, 2, 6, 4, 8, 2, 12, 2, 4, 6, 6, 4, 8, 2, 10, 5, 4, 2, 12, 4, 4, 4, 8, 2, 12, 4, 6, 4, 4, 4, 12, 2, 6, 6, 9 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Identical to A000005(n), the number of divisors of n, for n <= 1000.

As the size of the multiplication table grows, sequences of this kind approach A000005: the number of divisors of n. Any entry becomes stable once the size equals or exceeds n. - Robert G. Wilson v, Aug 03 2010

LINKS

T. D. Noe, Table of n, a(n) for n = 1..10000

FORMULA

a(n) = 0 for n > 10^6.

EXAMPLE

a(2)=2 because the number 2 appears in 2 cells in a 1000x1000 multiplication table.

MATHEMATICA

nn = 1000; mtab = Flatten[Table[i*j, {i, nn}, {j, nn}]]; Table[Count[mtab, n], {n, 10000}]

PROG

(PARI) a(n)=sumdiv(n, d, d<1001 && n/d<1001) \\ Charles R Greathouse IV, Dec 27 2016

CROSSREFS

Cf. A179940, A179941.

Sequence in context: A134687 A184395 A179941 * A000005 A122667 A122668

Adjacent sequences:  A179939 A179940 A179941 * A179943 A179944 A179945

KEYWORD

nonn,fini,less

AUTHOR

Dominick Cancilla, Aug 02 2010

EXTENSIONS

Rephrased observations as facts - R. J. Mathar, Aug 03 2010

STATUS

approved

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Last modified February 22 09:44 EST 2018. Contains 299449 sequences. (Running on oeis4.)