This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A098389 #8 Nov 21 2013 12:48:22 %S A098389 1,2,3,5,8,10,13,15,19,25,27,32,36,38,42,48,54,56,61,65,67,73,77,83, %T A098389 91,95,97,101,103,107,121,124,130,132,142,144,150,156,160,166,172,174, %U A098389 184,186,190,192,204,216,220,222,226,232,234,244,249,255,261,263,269,273 %N A098389 Prime(n) - floor(log_2(prime(n))). %C A098389 a(n) = A000040(n) - A098388(n). %e A098389 a(10) = A000040(10) - A098388(10) = 29 - 4 = 25. %t A098389 #-Floor[Log[2,#]]&/@Prime[Range[60]] (* _Harvey P. Dale_, Nov 06 2011 *) %o A098389 (PARI) a(n)=my(p=prime(n));p-log(p+.5)\log(2) \\ _Charles R Greathouse IV_, May 29 2013 %Y A098389 Cf. A000523, A098390, A014689, A098386, A098392. %K A098389 nonn %O A098389 1,2 %A A098389 _Reinhard Zumkeller_, Sep 06 2004