OFFSET
1,2
COMMENTS
In other words, except for row 1, row n contains the unitary prime power divisors of n, sorted by the prime. - Franklin T. Adams-Watters, May 05 2011
LINKS
Reinhard Zumkeller, Rows n=1..10000 of triangle, flattened
Eric Weisstein's World of Mathematics, Prime Factorization
FORMULA
EXAMPLE
60 has the prime factorization 2^2 * 3^1 * 5^1, so row 60 is (4,3,5).
From M. F. Hasler, Oct 12 2018: (Start)
The table starts:
n : largest prime powers dividing n
1 : 1
2 : 2
3 : 3
4 : 4
5 : 5
6 : 2, 3
7 : 7
8 : 8
9 : 9
10 : 2, 5
11 : 11
12 : 4, 3
etc. (End)
MATHEMATICA
f[{x_, y_}] := x^y; Table[Map[f, FactorInteger[n]], {n, 1, 50}] // Grid (* Geoffrey Critzer, Apr 03 2015 *)
PROG
(Haskell)
a141809 n k = a141809_row n !! (k-1)
a141809_row 1 = [1]
a141809_row n = zipWith (^) (a027748_row n) (a124010_row n)
a141809_tabf = map a141809_row [1..]
-- Reinhard Zumkeller, Mar 18 2012
(PARI) A141809_row(n)=if(n>1, [f[1]^f[2]|f<-factor(n)~], [1]) \\ M. F. Hasler, Oct 12 2018, updated Aug 19 2022
CROSSREFS
KEYWORD
nonn,tabf
AUTHOR
Leroy Quet, Jul 07 2008
STATUS
approved