A063008 Canonical partition sequence (see A080577) encoded by prime factorization. The partition [p1,p2,p3,...] with p1 >= p2 >= p3 >= ... is encoded as 2^p1 * 3^p2 * 5^p3 * ... .
1, 2, 4, 6, 8, 12, 30, 16, 24, 36, 60, 210, 32, 48, 72, 120, 180, 420, 2310, 64, 96, 144, 240, 216, 360, 840, 900, 1260, 4620, 30030, 128, 192, 288, 480, 432, 720, 1680, 1080, 1800, 2520, 9240, 6300, 13860, 60060, 510510, 256, 384, 576, 960, 864, 1440, 3360
Offset: 0
Examples
Partition [2,1,1,1] for n=5 gives 2^2*3*5*7 = 420. The sequence begins: 1; 2; 4, 6; 8, 12, 30; 16, 24, 36, 60, 210; 32, 48, 72, 120, 180, 420, 2310; 64, 96, 144, 240, 216, 360, 840, 900, 1260, 4620, 30030; ...
Links
- Alois P. Heinz, Rows n = 0..30, flattened
- S.-H. Cha, E. G. DuCasse, and L. V. Quintas, Graph Invariants Based on the Divides Relation and Ordered by Prime Signatures, arXiv:1405.5283 [math.NT], 2014.
Crossrefs
Programs
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Maple
with(combinat): A063008_row := proc(n) local e,w,r; r := proc(L) local B,i; B := NULL; for i from nops(L) by -1 to 1 do B := B,L[i] od; [%] end: w := proc(e) local i, m, p, P; m := infinity; P := permute([seq(ithprime(i),i=1..nops(e))]); for p in P do m := min(m,mul(p[i]^e[i],i=1..nops(e))) od end: [seq(w(e), e = r(partition(n)))] end: seq(print(A063008_row(i)),i=0..6); # Peter Luschny, Jan 23 2011 # second Maple program: b:= (n, i)-> `if`(n=0 or i=1, [[1$n]], [map(x-> [i, x[]], b(n-i, min(n-i, i)))[], b(n, i-1)[]]): T:= n-> map(x-> mul(ithprime(i)^x[i], i=1..nops(x)), b(n$2))[]: seq(T(n), n=0..9); # Alois P. Heinz, Sep 03 2019
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Mathematica
row[n_] := Product[ Prime[k]^#[[k]], {k, 1, Length[#]}]& /@ IntegerPartitions[n]; Table[row[n], {n, 0, 8}] // Flatten (* Jean-François Alcover, Dec 10 2012 *) b[n_, i_] := b[n, i] = If[n == 0 || i == 1, {Table[1, {n}]},Join[ Prepend[#, i]& /@ b[n - i, Min[n - i, i]], b[n, i - 1]]]; T[n_] := Product[Prime[i]^#[[i]], {i, 1, Length[#]}]& /@ b[n, n]; T /@ Range[0, 9] // Flatten (* Jean-François Alcover, Jun 09 2021, after Alois P. Heinz *)
Formula
bigomega(T(n,k)) = n. - Andrew Howroyd, Mar 28 2020
Extensions
Partially edited by N. J. A. Sloane, May 15, at the suggestion of R. J. Mathar
Corrected and (minor) edited by Daniel Forgues, Jan 03 2011
Comments