A348882 - OEIS

%I #26 Dec 23 2021 12:39:35

%S 16,48,72,96,144,432,576,1296,2592,5184,20736,32805,221184,1555200,

%T 11197440,55987200,95551488,268738560,302330880,382205952,524880000,

%U 671846400,6718464000,34012224000,155520000000,403107840000,6856864358400,107495424000000,110075314176000

%N Numbers that are expressible as the product of the number of distinct prime factors of preceding integers.

%e The number of distinct prime factors of the numbers 15, 14, 13, 12, 11, 10 are respectively 2, 2, 1, 2, 1, 2 and 2*2*1*2*1*2 = 16, hence 16 is a term.

%t om[n_] := om[n] = PrimeNu[n]; q[n_] := Module[{m = n, k = n - 1}, While[k > 1 && Divisible[m, om[k]], m /= om[k]; k--]; m == 1]; Select[Range[2, 10^6], q] (* _Amiram Eldar_, Nov 02 2021 *)

%Y Cf. A001221, A000961, A007774, A033992, A033993, A051270, A074969, A176655, A348266.

%K nonn

%O 1,1

%A _Metin Sariyar_, Nov 02 2021

%E a(13)-a(17) from _Amiram Eldar_, Nov 02 2021

%E More terms from _David A. Corneth_, Nov 02 2021