A153804 - OEIS

%I #15 Oct 21 2024 04:36:23

%S 0,0,0,0,1,2,1,6,19,30,38,45,240,282,616,1075,1111,1578,2093,2176,

%T 4808,4931,5565,9924,10802,11554,22197,43068,55197,65968,107982,

%U 378354,429648,628824,699060,1488035,1510610,3486215,6733375,10497919,12018202,12982385,15201133

%N a(n) = A153801(n)/2.

%H Amiram Eldar, <a href="/A153804/b153804.txt">Table of n, a(n) for n = 1..48</a>

%F a(n) = (A000043(n) - A000040(n))/2.

%t With[{max = 48}, (MersennePrimeExponent[Range[max]] - Prime[Range[max]]) / 2] (* _Amiram Eldar_, Oct 21 2024 *)

%Y Cf. A000040, A000043, A153800, A153801, A153802.

%K nonn

%O 1,6

%A _Omar E. Pol_, Jan 13 2009

%E More terms from _R. J. Mathar_, Mar 14 2009

%E More terms from _Jinyuan Wang_, Mar 02 2020