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 A202606 #29 Jul 01 2025 21:40:10
%S A202606 1,2,67,6217,617717,61732717,6172882717,617284382717,61728399382717,
%T A202606 6172839549382717,617283951049382717,61728395066049382717,
%U A202606 6172839506216049382717,617283950617716049382717,61728395061732716049382717,6172839506172882716049382717
%N A202606 a(n) = ceiling(((10^n - 1)^2/9 + 10^n)/18).
%C A202606 a(n) are distinct primes for n = 1 to 8.
%H A202606 Arkadiusz Wesolowski, <a href="/A202606/b202606.txt">Table of n, a(n) for n = 0..100</a>
%H A202606 G. L. Honaker, Jr. and Chris Caldwell, <a href="https://t5k.org/curios/cpage/15605.html">Prime Curios! 8</a>
%H A202606 <a href="/index/Rec#order_03">Index entries for linear recurrences with constant coefficients</a>, signature (111,-1110,1000).
%F A202606 a(n) = ceiling(((10^n - 1)^2/9 + 10^n)/18).
%F A202606 a(n) = (10^n - 1)*((10^n - 1)/9 + 1)/18 + 1.
%F A202606 G.f.: (1 - 109*x + 955*x^2)/((1 - x)*(1 - 10*x)*(1 - 100*x)).
%e A202606 a(2) = 67 because (99^2/9 + 100)/18 = 66.05555....
%p A202606 seq(((10^n-1)^2/9+10^n-1)/18+1, n=0..15);
%t A202606 Table[a = (10^n - 1)/18; 2*a^2 + a + 1, {n, 0, 15}]
%t A202606 LinearRecurrence[{111,-1110,1000},{1,2,67},20] (* _Harvey P. Dale_, Jul 07 2017 *)
%o A202606 (Magma) [ ((10^n-1)^2/9+10^n-1)/18+1 : n in [0..15]];
%o A202606 (PARI) for(n=0, 15, print1(((10^n-1)^2/9+10^n-1)/18+1, ", "))
%Y A202606 Cf. A000217, A002275, A084849.
%K A202606 easy,nonn
%O A202606 0,2
%A A202606 _Arkadiusz Wesolowski_, Dec 21 2011