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A102415 Greatest semiprime less than n-th prime. 4

%I

%S 4,6,10,10,15,15,22,26,26,35,39,39,46,51,58,58,65,69,69,77,82,87,95,

%T 95,95,106,106,111,123,129,134,134,146,146,155,161,166,169,178,178,

%U 187,187,194,194,209,221,226,226,226,237,237,249,254,262,267,267,274,278,278

%N Greatest semiprime less than n-th prime.

%C a(n) < A000040(n) < A102414(n).

%H Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/Semiprime.html">Semiprime</a>

%o (PARI) a(n) = {sp = prime(n)-1; while(bigomega(sp) != 2, sp--); sp;} \\ _Michel Marcus_, Mar 04 2017

%Y Cf. A001358, A102440.

%K nonn

%O 3,1

%A _Reinhard Zumkeller_, Jan 08 2005

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Last modified November 11 22:31 EST 2019. Contains 329046 sequences. (Running on oeis4.)