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 A385917 #22 Jul 28 2025 10:42:09
%S A385917 0,1,10296,98862891,949281469786,9115000574022981,
%T A385917 87522234562487194476,840388487154001467336271,
%U A385917 8069410166130487526875680366,77482475574796454079058815538761,743986722399785385936635219927503456,7143760431000263700967117302685072646451,68594386914477809656900874403746847623719746
%N A385917 Hexagonal numbers that are one-sixth of another hexagonal number.
%H A385917 Paolo Xausa, <a href="/A385917/b385917.txt">Table of n, a(n) for n = 1..250</a>
%H A385917 <a href="/index/Rec#order_03">Index entries for linear recurrences with constant coefficients</a>, signature (9603,-9603,1).
%F A385917 a(n) = A077289(A016813(n)) for n > 1.
%e A385917 10296 is a term because both 10296 and 6 * 10296 are hexagonal numbers.
%t A385917 LinearRecurrence[{9603, -9603, 1}, {0, 1, 10296, 98862891}, 15] (* _Paolo Xausa_, Jul 28 2025 *)
%Y A385917 Cf. A000384, A016813, A077289.
%K A385917 nonn
%O A385917 1,3
%A A385917 _Kelvin Voskuijl_, Jul 12 2025