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 A047947 #19 Aug 10 2024 01:29:45 %S A047947 2,4,2,4,4,4,6,4,2,4,6,6,2,6,4,6,4,6,4,4,6,4,6,10,4,6,6,4,6,4,6,6,4,2, %T A047947 4,6,8,6,4,2,8,4,10,2,4,10,10,4,6,6,2,10,6,2,6,4,6,12,4,6,10,4,6,6,6, %U A047947 8,6,10,4,8,6,6,2,6,12,10,2,4,6,6,8,4,2,10,8,6,6,4,8,10,2,6,4,2 %N A047947 a(n) is the number of k values for which A023193(k) = n. %C A047947 The old name was: "Schinzel's rhobar(n), number of distinct lengths of a block of consecutive integers on which a maximum of n primes occurs infinitely often (under the k-tuple conjecture)." [Note that "rhobar" is A023193.] %D A047947 Computed by _Achim Flammenkamp_. %e A047947 A block of 21 through 26 consecutive integers may contain at most 7 primes infinitely often. There are 6 possible lengths (21 through 26), so rhobar(7) = 6. %Y A047947 First differences of A020497. Cf. A008407, A023193. %K A047947 nonn %O A047947 1,1 %A A047947 _David W. Wilson_ %E A047947 Definition corrected by _Wolfdieter Lang_, Oct 07 2017