

A360459


Two times the median of the multiset of prime factors of n; a(1) = 2.


13



2, 4, 6, 4, 10, 5, 14, 4, 6, 7, 22, 4, 26, 9, 8, 4, 34, 6, 38, 4, 10, 13, 46, 4, 10, 15, 6, 4, 58, 6, 62, 4, 14, 19, 12, 5, 74, 21, 16, 4, 82, 6, 86, 4, 6, 25, 94, 4, 14, 10, 20, 4, 106, 6, 16, 4, 22, 31, 118, 5, 122, 33, 6, 4, 18, 6, 134, 4, 26, 10, 142, 4, 146
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OFFSET

1,1


COMMENTS

The median of a multiset is either the middle part (for odd length), or the average of the two middle parts (for even length). Since the denominator is always 1 or 2, the median can be represented as an integer by multiplying by 2.


LINKS



EXAMPLE

The prime factors of 60 are {2,2,3,5}, with median 5/2, so a(60) = 5.


MATHEMATICA

Table[2*Median[Join@@ConstantArray@@@FactorInteger[n]], {n, 100}]


CROSSREFS

The version for divisors is A063655.
Positions of odd terms are A072978 (except 1).
Positions of even terms are A359913 (and 1).
The version for prime indices is A360005.
The version for distinct prime indices is A360457.
The version for distinct prime factors is A360458.
The version for prime multiplicities is A360460.
The version for 0prepended differences is A360555.
Cf. A000975, A026424, A027336, A078174, A316413, A359907, A359908, A360006, A360007, A360248, A360552.


KEYWORD

nonn


AUTHOR



STATUS

approved



