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A087443 Least integer of each prime signature ordered first by sum of exponents and then by least integer value. 12
1, 2, 4, 6, 8, 12, 30, 16, 24, 36, 60, 210, 32, 48, 72, 120, 180, 420, 2310, 64, 96, 144, 216, 240, 360, 840, 900, 1260, 4620, 30030, 128, 192, 288, 432, 480, 720, 1080, 1680, 1800, 2520, 6300, 9240, 13860, 60060, 510510, 256, 384, 576, 864, 960, 1296, 1440 (list; graph; refs; listen; history; text; internal format)
OFFSET
0,2
COMMENTS
A025487 in a different order.
LINKS
EXAMPLE
1;
2;
4,6;
8,12,30;
16,24,36,60,210;
32,48,72,120,180,420,2310;
64,96,144,216,240,360,840,900,1260,4620,30030;
128,192,288,432,480,720,1080,1680,1800,2520,6300,9240,13860,60060,510510;
MAPLE
b:= proc(n, i, l)
`if`(n=0, [mul(ithprime(t)^l[t], t=1..nops(l))],
`if`(i=1, b(0, 0, [l[], 1$n]), [b(n, i-1, l)[],
`if`(i>n, [], b(n-i, i, [l[], i]))[]]))
end:
T:= n-> sort(b(n$2, []))[]:
seq(T(n), n=0..10); # Alois P. Heinz, Jun 13 2012
MATHEMATICA
b[n_, i_, l_] := b[n, i, l] = If[n == 0, Join[{Product[Prime[t]^l[[t]], {t, 1, Length[l]}]}], If[i == 1, b[0, 0, Join[l, Table[1, {n}]]], Join[b[n, i - 1, l], If[i > n, {}, b[n - i, i, Append[l, i]]]]]];
T[n_] := Sort[b[n, n, {}]];
Table[T[n], {n, 0, 10}] // Flatten (* Jean-François Alcover, Apr 06 2017, after Alois P. Heinz *)
CROSSREFS
Sequence in context: A173941 A194406 A371164 * A059901 A036035 A063008
KEYWORD
nonn,tabf
AUTHOR
Ray Chandler, Sep 04 2003
STATUS
approved

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Last modified June 22 10:49 EDT 2024. Contains 373570 sequences. (Running on oeis4.)