OFFSET
1,2
FORMULA
T(n,k) = Sum_{p=2..floor(n^(1/(k-1)))} phi(p)*floor(n/p^(k-1)) where phi is the Euler phi-function A000010 and k runs from 1 to 1+floor(log_2(n))}.
EXAMPLE
Triangle begins:
[1],
[2, 1],
[3, 3],
[4, 6, 1],
[5, 10, 1],
[6, 15, 1],
[7, 21, 1],
[8, 28, 2, 1],
[9, 36, 4, 1],
[10, 45, 4, 1],
[11, 55, 4, 1],
[12, 66, 5, 1],
[13, 78, 5, 1],
[14, 91, 5, 1],
[15, 105, 5, 1],
[16, 120, 8, 2, 1],
...
MAPLE
CROSSREFS
KEYWORD
nonn,tabf
AUTHOR
Scott R. Shannon and N. J. A. Sloane, Oct 23 2023
STATUS
approved