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A100635 Number of 2 X 2 matrices with elements in {1,2,...,n} such that LCMs of rows and columns are n. 0
1, 7, 7, 17, 7, 49, 7, 31, 17, 49, 7, 119, 7, 49, 49, 49, 7, 119, 7, 119, 49, 49, 7, 217, 17, 49, 31, 119, 7, 343, 7, 71, 49, 49, 49, 289, 7, 49, 49, 217, 7, 343, 7, 119, 119, 49, 7, 343, 17, 119, 49, 119, 7, 217, 49, 217, 49, 49, 7, 833, 7, 49, 119 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Table of n, a(n) for n=1..63.

FORMULA

Multiplicative with a(p^e) = 2*(e+1)^2-1.

CROSSREFS

Cf. A048691.

Sequence in context: A120682 A152910 A198439 * A168458 A165138 A196395

Adjacent sequences:  A100632 A100633 A100634 * A100636 A100637 A100638

KEYWORD

mult,easy,nonn

AUTHOR

Vladeta Jovovic, Dec 03 2004

STATUS

approved

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Last modified March 23 21:31 EDT 2017. Contains 283985 sequences.