A367858 Irregular triangle read by rows where row n is the multiset multiplicity cokernel (MMC) of the multiset of prime indices of n.

1, 2, 1, 3, 2, 2, 4, 1, 2, 3, 3, 5, 1, 2, 6, 4, 4, 3, 3, 1, 7, 1, 2, 8, 1, 3, 4, 4, 5, 5, 9, 1, 2, 3, 6, 6, 2, 1, 4, 10, 3, 3, 3, 11, 1, 5, 5, 7, 7, 4, 4, 2, 2, 12, 8, 8, 6, 6, 1, 3, 13, 4, 4, 4, 14, 1, 5, 2, 3, 9, 9, 15, 1, 2, 4, 1, 3, 7, 7, 1, 6, 16, 1, 2

Offset

1,2

Comments

Row n = 1 is empty.

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.

We define the multiset multiplicity cokernel MMC(m) of a multiset m by the following property, holding for all distinct multiplicities k >= 1. If S is the set of elements of multiplicity k in m, then max(S) has multiplicity |S| in MMC(m). For example, MMC({1,1,2,2,3,4,5}) = {2,2,5,5,5}, and MMC({1,2,3,4,5,5,5,5}) = {4,4,4,4,5}.

Links

Table of n, a(n) for n=1..84.

Formula

For all positive integers n and k, row n^k is the same as row n.

Example

The first 45 rows:
     1: {}       16: {1}        31: {11}
     2: {1}      17: {7}        32: {1}
     3: {2}      18: {1,2}      33: {5,5}
     4: {1}      19: {8}        34: {7,7}
     5: {3}      20: {1,3}      35: {4,4}
     6: {2,2}    21: {4,4}      36: {2,2}
     7: {4}      22: {5,5}      37: {12}
     8: {1}      23: {9}        38: {8,8}
     9: {2}      24: {1,2}      39: {6,6}
    10: {3,3}    25: {3}        40: {1,3}
    11: {5}      26: {6,6}      41: {13}
    12: {1,2}    27: {2}        42: {4,4,4}
    13: {6}      28: {1,4}      43: {14}
    14: {4,4}    29: {10}       44: {1,5}
    15: {3,3}    30: {3,3,3}    45: {2,3}

Mathematica

mmc[q_]:=With[{mts=Length/@Split[q]}, Sort[Table[Max@@Select[q, Count[q, #]==i&], {i, mts}]]];
Table[mmc[PrimePi /@ Join@@ConstantArray@@@If[n==1, {}, FactorInteger[n]]], {n, 100}]

Crossrefs

Indices of empty and singleton rows are A000961.

Row lengths are A001221.

Depends only on rootless base A052410, see A007916.

Row maxima are A061395.

Rows have A071625 distinct elements.

Indices of constant rows are A072774.

Indices of strict rows are A130091.

Row minima are A367587.

Rows have Heinz numbers A367859.

Row sums are A367860.

Sorted row indices of first appearances are A367861, for kernel A367585.

A007947 gives squarefree kernel.

A112798 lists prime indices, length A001222, sum A056239, reverse A296150.

A124010 lists prime multiplicities (prime signature), sorted A118914.

A181819 gives prime shadow, with an inverse A181821.

A238747 gives prime metasignature, reversed A353742.

A304038 lists distinct prime indices, length A001221, sum A066328.

Cf. A000720, A027746, A051904, A052409, A061395, A175781, A367582, A367583.

Sequence in context: A090350 A199133 A199246 * A363718 A200649 A298742

Adjacent sequences: A367855 A367856 A367857 * A367859 A367860 A367861

Keyword

nonn,tabf

Author

Gus Wiseman, Dec 03 2023

Status

approved