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 A068007 #7 Jan 18 2024 16:08:48 %S A068007 1,2,5,7,10,11,15,21,0,22,23,31,34,38,35,45,50,46,47,53,62,58,59,67, %T A068007 69,84,70,71,79,83,87,92,93,101,94,105,95,106,107,116,117,122,118,125, %U A068007 119,134,135,139,146,142,149,143,156,155,158,159,171,166,167,176,175,185 %N A068007 Least number k such that the number of primes of the form [k/j] for j=1..k (A068050) is n, or zero if impossible. %C A068007 a(n) = 0 for n = 8, 94, 103, 122, 180, 283, 311, 353, 355, 398, ... %t A068007 f[n_] := Count[ PrimeQ[ Floor[ n/Table[i, {i, Floor[n/2]} ]]], True]; a = Table[0, {100} ]; Do[b = f[n]; If[b < 100 && a[[b + 1]] == 0, a[[b + 1]] = n], {n, 1, 300}]; a %Y A068007 Cf. A068050. %K A068007 nonn %O A068007 0,2 %A A068007 _Robert G. Wilson v_, Feb 12 2002 %E A068007 Name corrected by _Sean A. Irvine_, Jan 18 2024