OFFSET
1,2
COMMENTS
LINKS
Rémy Sigrist, Table of n, a(n) for n = 1..10001 (rows for n = 1..4045)
EXAMPLE
Triangle begins:
1 [1]
2 [2]
3 [3]
4 [2]
5 [5]
6 [2, 3]
7 [7]
8 [2, 3]
9 [2, 3]
10 [2, 5]
11 [11]
12 [2, 3]
13 [13]
14 [2, 7]
15 [3, 5]
PROG
(PARI) row(n) = { my (f=factor(n), p=f[, 1]~); for (k=1, #f~, if (f[k, 2]>1, p=concat(p, row(f[k, 2]))); ); if (#p==0, [1], Set(p)) }
CROSSREFS
KEYWORD
nonn,tabf
AUTHOR
Rémy Sigrist, Aug 09 2020
STATUS
approved