|
| |
|
|
A074963
|
|
Max ( sigma(x*y) : 1<=x<=n, 1<=y<=n ).
|
|
3
| |
|
|
1, 7, 13, 31, 42, 91, 96, 127, 195, 234, 234, 403, 403, 480, 576, 744, 744, 847, 847, 1170, 1344, 1344, 1344, 1651, 1860, 1860, 1860, 2240, 2240, 2880, 2880, 3048, 3048, 3048, 3048, 4368, 4368, 4368, 4368, 5040, 5040, 5952, 5952, 5952, 6552, 6552, 6552
(list; graph; refs; listen; history; internal format)
|
|
|
|
OFFSET
| 1,2
|
|
|
COMMENTS
| Does a(n)=sigma(n^2) for a finite number of values of n (1,2,3,4,6,8,12,18,24,60) ? See A074964.
|
|
|
LINKS
| Reinhard Zumkeller, Table of n, a(n) for n = 1..750
|
|
|
MAPLE
| A074963 := proc(n)
a := 0 ;
for x from 1 to n do
for y from 1 to x do
a := max(a, numtheory[sigma](x*y)) ;
end do:
end do;
a ;
end proc: # R. J. Mathar, Sep 27 2011
|
|
|
PROG
| (PARI) a(n)=vecmax(matrix(n, n, x, y, sigma(x*y)))
(Haskell)
a074963 n = maximum [a000203 (x*y) | x <- [1..n], y <- [x..n]]
-- Reinhard Zumkeller, Nov 14 2011
|
|
|
CROSSREFS
| Cf. A000203.
Sequence in context: A046139 A023243 A087196 * A110912 A085104 A162652
Adjacent sequences: A074960 A074961 A074962 * A074964 A074965 A074966
|
|
|
KEYWORD
| easy,nonn
|
|
|
AUTHOR
| Benoit Cloitre (benoit7848c(AT)orange.fr), Oct 05 2002
|
| |
|
|
