

A238689


Table read by rows: first row is {1}; for n >1, T(n, k) is the kth largest prime factor of n (repeated prime factors are counted repeatedly).


2



1, 2, 3, 2, 2, 5, 3, 2, 7, 2, 2, 2, 3, 3, 5, 2, 11, 3, 2, 2, 13, 7, 2, 5, 3, 2, 2, 2, 2, 17, 3, 3, 2, 19, 5, 2, 2, 7, 3, 11, 2, 23, 3, 2, 2, 2, 5, 5, 13, 2, 3, 3, 3, 7, 2, 2, 29, 5, 3, 2, 31, 2, 2, 2, 2, 2, 11, 3, 17, 2, 7, 5, 3, 3, 2, 2, 37, 19, 2, 13, 3, 5, 2, 2, 2
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OFFSET

1,2


COMMENTS

nth row has length 1 if n = 1, A001222(n) if n > 1.


LINKS

Peter Kagey, Table of n, a(n) for n = 1..10000


FORMULA

Row n is row n of A027746 in reverse order.


EXAMPLE

Table begins:
1;
2;
3;
2,2;
5;
3,2;
7;
2,2,2;
3,3;
5,2;
...


PROG

(Haskell)
a238689_row 1 = [1]
a238689_row n = a n [] a000040_list where
a m factors ps@(p:ps')
 m == 1 = factors
 m `mod` p == 0 = a (m `div` p) (p : factors) ps
 otherwise = a m factors ps'
a _ _ [] = []  Peter Kagey, Sep 15 2016


CROSSREFS

First column is A006530; numbers along right boundary form A020639.
A001414 gives row sums (for n > 1).
Cf. A027746, A238690.
Sequence in context: A207338 A027746 A240230 * A166454 A283239 A128651
Adjacent sequences: A238686 A238687 A238688 * A238690 A238691 A238692


KEYWORD

nonn,tabf


AUTHOR

Matthew Vandermast, Apr 28 2014


STATUS

approved



