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A090958 Numbers in increasing order such that the least multiple of prime(n) in the sequence is primorial(n). 1

%I

%S 1,2,4,6,8,9,12,16,18,24,27,30,32,36,40,45,48,50,54,60,64,72,75,80,81,

%T 90,96,100,108,120,125,128,135,144,150,160,162,180,192,200,210,216,

%U 224,225,240,243,245,250,252,256,270,280,288,294,300,315,320,324,336,343

%N Numbers in increasing order such that the least multiple of prime(n) in the sequence is primorial(n).

%C The sequence is obtained by including all those numbers between primorial(n) and primorial(n+1) which have the largest prime divisor < = prime(n).

%t {{1}}~Join~Array[Function[{p, q}, Select[Range[p, p NextPrime[q] - 1], FactorInteger[#][[-1, 1]] <= q &]] @@ {Product[Prime@ i, {i, #}], Prime[#]} &, 4] // Flatten (* _Michael De Vlieger_, Nov 18 2017 *)

%o (PARI) v = vector(1000); pr = 1; forprime(p = 2, 1000, pr *= p; v[p] = pr); for (n = 2, 1000, f = factor(n); p = f[matsize(f)[1], 1]; if (n >= v[p], print(n))); \\ _David Wasserman_, Feb 22 2006

%Y Cf. A090959.

%K nonn

%O 0,2

%A _Amarnath Murthy_, Dec 31 2003

%E More terms from _David Wasserman_, Feb 22 2006

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Last modified January 26 03:19 EST 2022. Contains 350572 sequences. (Running on oeis4.)