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 A029834 #17 Jul 08 2025 19:22:40 %S A029834 0,0,1,0,1,0,1,0,0,0,2,0,2,0,0,0,2,0,2,0,0,0,3,0,0,0,0,0,3,0,3,0,0,0, %T A029834 0,0,3,0,0,0,3,0,3,0,0,0,3,0,0,0,0,0,3,0,0,0,0,0,4,0,4,0,0,0,0,0,4,0, %U A029834 0,0,4,0,4,0,0,0,0,0,4,0,0,0,4,0,0,0,0,0,4,0,0,0,0,0,0,0,4,0,0,0,4,0,4,0,0,0,4,0,4,0,0,0,4,0,0 %N A029834 A discrete version of the Mangoldt function: if n is prime then floor(log(n)) else 0. %C A029834 The real Mangoldt function Lambda(n) is equal to log(n) if n is prime else 0. %D A029834 T. M. Apostol, Introduction to Analytic Number Theory, Springer-Verlag, 1976, page 32. %D A029834 Paulo Ribenboim, Algebraic Numbers, p. 44. %H A029834 Antti Karttunen, <a href="/A029834/b029834.txt">Table of n, a(n) for n = 1..65539</a> %t A029834 Array[If[PrimeQ[#], Floor[Log[#]], 0] &, 80] (* _Harvey P. Dale_, Jul 24 2013 *) %o A029834 (PARI) v=[]; for(n=1,150,v=concat(v, if(isprime(n),floor(log(n)),))); v %o A029834 (PARI) A029834(n) = if(!isprime(n),0,floor(log(n))); \\ _Antti Karttunen_, Feb 06 2019 %Y A029834 Cf. A029832, A029833, A053821, A062950. %K A029834 nonn,easy %O A029834 1,11 %A A029834 _N. J. A. Sloane_ %E A029834 More terms from _Antti Karttunen_, Feb 06 2019