OFFSET
1,2
COMMENTS
A prime index of n is a number m such that prime(m) divides n. The multiset of prime indices of n is row n of A112798.
The minima of strictly increasing runs in a sequence are obtained by splitting it into maximal strictly increasing subsequences and taking the first term of each.
LINKS
EXAMPLE
The prime indices of 540 are {1,1,2,2,2,3}, with strictly increasing runs ({1},{1,2},{2},{2,3}), with minima (1,1,2,2), which is row 540.
Triangle begins:
1:
2: 1
3: 2
4: 1 1
5: 3
6: 1
7: 4
8: 1 1 1
9: 2 2
10: 1
11: 5
12: 1 1
13: 6
14: 1
15: 2
16: 1 1 1 1
MATHEMATICA
Table[If[n==1, {}, First/@Split[Flatten[Cases[FactorInteger[n], {p_, k_}:>Table[PrimePi[p], {k}]]], Less]], {n, 100}]
CROSSREFS
KEYWORD
nonn,tabf
AUTHOR
Gus Wiseman, Aug 04 2024
STATUS
approved