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A339489 T(n, k) = Product(divisors(k) union {k*j : j = 2..floor(n/k)}). Triangle read by rows. 3
1, 2, 2, 6, 2, 3, 24, 8, 3, 8, 120, 8, 3, 8, 5, 720, 48, 18, 8, 5, 36, 5040, 48, 18, 8, 5, 36, 7, 40320, 384, 18, 64, 5, 36, 7, 64, 362880, 384, 162, 64, 5, 36, 7, 64, 27, 3628800, 3840, 162, 64, 50, 36, 7, 64, 27, 100, 39916800, 3840, 162, 64, 50, 36, 7, 64, 27, 100, 11 (list; table; graph; refs; listen; history; text; internal format)
OFFSET
1,2
COMMENTS
For the connection with paths in the divisor graph of {1,...,n} see the comment in A339492.
LINKS
EXAMPLE
The triangle starts:
[1] 1;
[2] 2, 2;
[3] 6, 2, 3;
[4] 24, 8, 3, 8;
[5] 120, 8, 3, 8, 5;
[6] 720, 48, 18, 8, 5, 36;
[7] 5040, 48, 18, 8, 5, 36, 7;
[8] 40320, 384, 18, 64, 5, 36, 7, 64;
[9] 362880, 384, 162, 64, 5, 36, 7, 64, 27;
[10] 3628800, 3840, 162, 64, 50, 36, 7, 64, 27, 100;
MAPLE
t := (n, k) -> NumberTheory:-Divisors(k) union {seq(k*j, j=2..n/k)}:
T := (n, k) -> mul(j, j = t(n, k)):
for n from 1 to 10 do seq(T(n, k), k=1..n) od;
CROSSREFS
T(n, 1) = A000142(n), T(n, n) = A007955(n).
Sequence in context: A281552 A205506 A110141 * A293443 A247765 A129750
KEYWORD
nonn,tabl
AUTHOR
Peter Luschny, Dec 31 2020
STATUS
approved

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Last modified March 28 11:59 EDT 2024. Contains 371254 sequences. (Running on oeis4.)