_Giovanni Teofilatto (g.teofilatto(AT)tiscalinet.it), _, Apr 27 2005

OEIS Server: https://oeis.org/edit/global/226

easy,nonn,new

More terms from Reinhard Zumkeller (reinhard.zumkeller(AT)lhsystemsgmail.com), May 03 2005

Eric W. Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/AlmostPrime.html">Almost Prime</a>.

easy,nonn,new

3-almost primes of the form prime(n) + prime(n+1).

8, 12, 18, 30, 42, 52, 68, 78, 138, 172, 186, 222, 258, 268, 410, 434, 508, 548, 618, 668, 762, 772, 786, 892, 906, 946, 978, 1002, 1030, 1132, 1334, 1374, 1446, 1542, 1606, 1758, 1866, 1878, 1948, 2006, 2022, 2252, 2334, 2414, 2452, 2468, 2486, 2572, 2588

1,1

Minimal "almost prime" of the form prime(n) + prime(n+1).

Eric W. Weisstein, <a href="http://mathworld.wolfram.com/AlmostPrime.html">Almost Prime</a>.

a(n) is equal to 3-almost prime if a semiprime is equal to the arithmetic mean of prime(n) and prime(n+1).

a(2)=12 because 12=5+7=3*2^2;

a(3)=18 because 18=7+11=2*3^2.

Cf. A014612.

easy,nonn

Giovanni Teofilatto (g.teofilatto(AT)tiscalinet.it), Apr 27 2005

More terms from Reinhard Zumkeller (reinhard.zumkeller(AT)lhsystems.com), May 03 2005

approved