OFFSET
1,2
COMMENTS
A051613 gives number of elements in n-th row.
LINKS
Alois P. Heinz, Rows n = 1..100, flattened
J. Bamberg, G. Cairns and D. Kilminster, The crystallographic restriction, permutations and Goldbach's conjecture, Amer. Math. Monthly, 110 (March 2003), 202-209.
FORMULA
n-th row = set of m such that A008475(m) = n, or 0 if no such m exists.
EXAMPLE
1;
2;
3;
4;
5, 6;
0;
7, 10, 12;
8, 15;
...
MAPLE
b:= proc(n) option remember; `if`(n<3, {n},
{n, seq(map(x-> ilcm(x, i), b(n-i))[], i=2..n-1)}
minus {seq(b(i)[], i=1..n-1)})
end:
T:= proc(n) local l; l:= [b(n, n)[]];
`if`(nops(l)=0, 0, sort(l)[])
end:
seq(T(n), n=1..20); # Alois P. Heinz, Feb 15 2013
MATHEMATICA
b[n_, i_] := b[n, i] = Module[{p}, p = If[i<1, 1, Prime[i]]; If[n == 0, 1, If[i<1 || n<0, 0, Max[Join[{b[n, i-1]}, Table[p^j*b[n-p^j, i-1], {j, 1, Log[p, n]}]]]]] ]; T[1] = {1}; T[6] = {0}; T[n_] := Reap[For[m = n, m <= b[n, PrimePi[n]], m++, If[n == Total[Power @@@ FactorInteger[m]], Sow[m]]]][[2, 1]]; Table[T[n], {n, 1, 20}] // Flatten (* Jean-François Alcover, Feb 26 2015, after Alois P. Heinz *)
CROSSREFS
KEYWORD
AUTHOR
N. J. A. Sloane, Mar 08 2003
EXTENSIONS
More terms from Vladeta Jovovic, Mar 12 2003
STATUS
approved