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 A183532 #12 May 02 2017 15:31:40 %S A183532 1,2,3,4,5,6,7,8,9,45,81,82,83,84,85,86,87,88,89,117,133,153,177,189, %T A183532 221,225,1325,1326,1328,1329,1373,1378,1379,1391,1392,1398,1423,1427, %U A183532 2717,2718,4031,4032,4035,4037,4039,5316,5319,5346,5352,5353,5354,5361 %N A183532 An Ulam-type sequence: a(n) = n if n<=9; for n>9, a(n) = least number > a(n-1) which is a unique sum of 9 distinct earlier terms. %C A183532 An Ulam-type sequence - see A002858 for further information. %H A183532 Alois P. Heinz, <a href="/A183532/b183532.txt">Table of n, a(n) for n = 1..200</a> %H A183532 <a href="/index/U#Ulam_num">Index entries for Ulam numbers</a> %e A183532 a(10) = 45 = 1 + ... + 9 = 9*10/2, because it is the least number >9 with a unique sum of 9 distinct earlier terms. %e A183532 a(11) = 81 = 1 + ... + 8 + 45 = 9^2, because it is the least number >45 with a unique sum of 9 distinct earlier terms. %p A183532 # see A183534 for programs. %Y A183532 Column k=9 of A183534. %Y A183532 Cf. A002858, A007086, A183527-A183533, A135737. %K A183532 nonn %O A183532 1,2 %A A183532 _Jonathan Vos Post_ and _Alois P. Heinz_, Jan 05 2011