A362266 Triangle read by rows: T(n,k) = LCM({p_j-1 : j=1..n})/(p_k-1) for prime p.

1, 2, 1, 4, 2, 1, 12, 6, 3, 2, 60, 30, 15, 10, 6, 60, 30, 15, 10, 6, 5, 240, 120, 60, 40, 24, 20, 15, 720, 360, 180, 120, 72, 60, 45, 40, 7920, 3960, 1980, 1320, 792, 660, 495, 440, 360, 55440, 27720, 13860, 9240, 5544, 4620, 3465, 3080, 2520, 1980

Offset: 1

Author

Michael De Vlieger, Jul 10 2023

Keywords

• nonn
• tabl

Examples

			First 10 rows of the triangle:
   1:      1
   2:      2      1
   3:      4      2      1
   4:     12      6      3     2
   5:     60     30     15    10     6
   6:     60     30     15    10     6     5
   7:    240    120     60    40    24    20    15
   8:    720    360    180   120    72    60    45    40
   9:   7920   3960   1980  1320   792   660   495   440   360
  10:  55440  27720  13860  9240  5544  4620  3465  3080  2520  1980
  ...
		

Links

• Michael De Vlieger, Table of n, a(n) for n = 1..11325 (rows n = 1..150, flattened)

Crossrefs

Cf. A006093, A058254.

Programs

Mathematica

nn = 10; Array[Set[s[#], Prime[#] - 1] &, nn + 1]; Flatten@ Table[Table[#/s[k], {k, n}] &[LCM @@ Array[s, n]], {n, nn}]

PARI

row(n) = my(L=lcm(apply(p->p-1, primes(n)))); vector(n, k, L/(prime(k)-1)); \\ Michel Marcus, Jul 15 2023

Formula

T(n,1) = A058254(n), T(n,k) = A058254(n)/A006093(k).