

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
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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



