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 A260409 #14 Aug 16 2015 15:14:14 %S A260409 8,16,18,27,45,50,54,60,64,84,99,132,147,153,162,207,220,225,228,240, %T A260409 242,243,245,255,256,264,280,297,315,325,336,338,343,348,364,369,375, %U A260409 423,425,435,440,455,460,468,475,477,486,487,507,539,552 %N A260409 Bisection of A260310. %C A260409 Greater (member) of the n-th pair in A260310. %C A260409 a(n) ~ 11.0*n. %C A260409 It appears that most of the terms are composite (97.25% out of the first 10000 terms), but there are some primes: 487, 983, 1093, 1231, 1277, 2143, 2207, 2749, ..., . %C A260409 a(n) < a(n+1) for all n > 0 is false, a(3276) = a(3277)= 35407 with A260409(3276) equal to 29820 & A260409(3276) equal to 34350 and a(4228) = a(4229) = 45841 with A260409(4228) equal to 40260 & A260409(4229) equal to 41496. %C A260409 Least term a(n) such that a(n+1) is k away: 3276, 21, 2, 18, 6, 5, 7, 44, 1, 3, ..., . (A260410). %C A260409 Conjecture: when a(n) is composite, A260408(n) is prime and vice versa. No contradictions in the first 10000 terms. %H A260409 Robert G. Wilson v, <a href="/A260409/b260409.txt">Table of n, a(n) for n = 1..9906</a> %F A260409 a(n) = A260310(2n). %e A260409 see A260310. %t A260409 (* first run the Mmca in A260310 and then *) Take[ Transpose[ lst][[2]], 60] %Y A260409 Cf. A260310, A260408, A260410. %K A260409 nonn %O A260409 1,1 %A A260409 _Robert G. Wilson v_, Jul 24 2015