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 A100143 #2 Mar 30 2012 17:36:43 %S A100143 1,2,4,6,10,14,18,22,28,34,40,46,52,58,68,78,88,98,108,118,128,138, %T A100143 148,158,172,186,200,214,228,242,256,270,284,298,312,326,340,354,372, %U A100143 390,408,426,444,462,480,498,516,534,552,570,588,606,624,642,660,678,700 %N A100143 Unique sequence with a(1)=1 where each a(n) occurs in the same order a(n) times consecutively in its sequence of first differences which contains no other terms. %C A100143 By definition, for each n the sequence contains exactly one arithmetic progression (beginning at the A100250(n)-th term) of length a(n)+1 with common difference a(n). Contrast with A075349 and its sequence of first differences, A002024, which includes each A075349(n) term A075349(n) times but also includes terms that are not found in A075349. %Y A100143 Cf. A100144 (first differences), A001462 (Golomb's sequence), A075349, A002024. %K A100143 nonn %O A100143 1,2 %A A100143 _Rick L. Shepherd_, Nov 09 2004