

A160401


Table read by antidiagonals: a(m,n) = the smallest composite multiple of both m and n.


0



4, 4, 4, 6, 4, 6, 4, 6, 6, 4, 10, 4, 6, 4, 10, 6, 10, 12, 12, 10, 6, 14, 6, 15, 4, 15, 6, 14, 8, 14, 6, 20, 20, 6, 14, 8, 9, 8, 21, 12, 10, 12, 21, 8, 9, 10, 18, 24, 28, 30, 30, 28, 24, 18, 10, 22, 10, 9, 8, 35, 6, 35, 8, 9, 10, 22, 12, 22, 30, 36, 40, 42, 42, 40, 36, 30, 22, 12, 26, 12, 33
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OFFSET

1,1


COMMENTS

a(p,1) = a(1,p) = a(p,p) = 2p, where p = any one prime. a(1,1) = 4. Otherwise, a(m,n) = lcm(m,n).


LINKS

Table of n, a(n) for n=1..81.


EXAMPLE

Array begins:
4, 4, 6, 4, 10, 6, ...
4, 4, 6, 4, 10, 6, ...
6, 6, 6, 12, 15, 6, ...
4, 4, 12, 4, 20, 12, ...
10, 10, 15, 20, 10, 30, ...
6, 6, 6, 12, 30, 6, ...
...


PROG

(PARI) T(n, k) = {my(j = lcm(n, k), c = j); while (isprime(c)  (c==1), c += j); c; }
tabl(nn) = for (n=1, nn, for (k=1, nn, print1(T(n, k), ", ")); print); \\ Michel Marcus, Mar 13 2018


CROSSREFS

Cf. A003990.
Sequence in context: A130331 A141241 A140696 * A114742 A273909 A098013
Adjacent sequences: A160398 A160399 A160400 * A160402 A160403 A160404


KEYWORD

nonn,tabl,changed


AUTHOR

Leroy Quet, May 12 2009


EXTENSIONS

Extended by Ray Chandler, Jun 18 2009


STATUS

approved



