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 A278489 #11 Nov 27 2016 22:06:24 %S A278489 0,3,6,8,9,11,15,16,18,19,21,24,27,30,32,35,38,39,40,41,43,45,48,50, %T A278489 51,53,54,56,59,63,64,66,67,70,71,72,73,74,75,78,80,81,83,85,87,88,90, %U A278489 91,93,95,96,99,102,104,105,107,108,111,112,114,115,117,120,123,126,128,129,130,131,134,135,136,137,138,139,143,144 %N A278489 Nonleaves in the tree defined by edge relation A255131(child) = parent, the least squares beanstalk. %C A278489 Numbers n for which there exists at least one such integer k that k - A002828(k) = n, in other words, numbers n such that either A002828(1+n) is 1 or A002828(2+n) is 2 or A002828(3+n) is 3 or A002828(4+n) is 4, as the maximum value that A002828 may obtain is 4. %C A278489 Indexing starts from zero, because a(0)=0 is a special case in this sequence. %H A278489 Antti Karttunen, <a href="/A278489/b278489.txt">Table of n, a(n) for n = 0..10000</a> %o A278489 (Scheme, with _Antti Karttunen_'s IntSeq-library) %o A278489 (define A278489 (NONZERO-POS 0 0 A278216)) %Y A278489 Complement: A278490. %Y A278489 Positions of nonzeros in A278216. %Y A278489 Cf. A276573 (the infinite trunk of the tree, is a subsequence). %Y A278489 Cf. A278491 (another subsequence). %Y A278489 Cf. A002828, A255131. %K A278489 nonn %O A278489 0,2 %A A278489 _Antti Karttunen_, Nov 25 2016