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%I #18 Jun 07 2024 14:59:52
%S 2,6,3,30,10,4,210,42,12,5,2310,330,60,14,7,30030,2730,390,66,15,8,
%T 510510,39270,3570,420,70,18,9,9699690,570570,43890,3990,462,78,20,11,
%U 223092870,11741730,690690,46410,4290,510,84,21,13,6469693230,281291010
%N Table read by ascending antidiagonals: n-th row of table consists of the positive integers divisible by exactly n distinct primes.
%C Concatenated sequence is a permutation of the integers >= 2.
%C The chosen encoding of the table by *rising* diagonals is contrary to the OEIS standard which rather expects falling diagonals: as a consequence, displaying this sequence as a table (2nd link after the list of terms above) will list the integers with given number of prime divisors in columns rather than rows. - _M. F. Hasler_, Jun 06 2024
%e The table begins:
%e n\k| 1 2 3 4 5 6 ...
%e -----+----------------------------------
%e 1 | 2, 3, 4, 5, 7, 8, ...
%e 2 | 6, 10, 12, 14, 15, ...
%e 3 | 30, 42, 60, ...
%e 4 | 210, 330, ...
%e ...| ...
%t f[n_, m_] := f[n, m] = Block[{c = m, k = If[m == 1, Product[Prime[i], {i, n}], f[n, m - 1] + 1]},While[Length@FactorInteger[k] != n, k++ ];k];Table[f[d - m + 1, m], {d, 10}, {m, d}] // Flatten (* _Ray Chandler_, Feb 08 2007 *)
%o (PARI) A125666(n, k=0)={if(k, for(m=vecprod(primes(n)), oo, omega(m)!=n || k-- || return(m)), A125666(A004736(n), A002260(n)))} \\ _M. F. Hasler_, Jun 06 2024
%Y Cf. A001221, A002110 (col 1), A246655 (row 1), A007774 (row 2), A033992 (row 3), A033993 (row 4), A051270 (row 5), A074969 (row 6), A176655 (row 7), A348072 (row 8), A348073 (row 9), A073329 (diag), compare to A048692.
%K nonn,tabl,changed
%O 1,1
%A _Leroy Quet_, Jan 29 2007
%E Extended by _Ray Chandler_, Feb 08 2007
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