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 A101172 #11 May 02 2025 01:32:36
%S A101172 1,2,3,5,8,15,26,51,97,191,373,745,1472,2943,5859,11708,23365,46729,
%T A101172 93349,186697,373200,746372,1492370,2984739,5968687,11937366,23873259,
%U A101172 47746421,95489896,190979791,381953529,763907057,1527802406,3055604437,6111185508
%N A101172 Sequence whose Mobius transform leads to the first differences of the terms.
%C A101172 In the example, the last value in the Mobius transform of [1,2,3,5,8] is 7 and so the next term in our sequence is 8+7=15. Then, the Mobius transform of [1,2,3,5,8,15] is [1,1,2,3,7,11], which means that the next term of our sequence is 15+11=26, etc.
%e A101172 For example, the Mobius transform of the segment [1,2,3,5,8] begins [1,1,2,3], which are the first differences of these terms.
%p A101172 with(numtheory): F:={1}: f:=n->F[n]: g:=n->sum(mobius(divisors(n)[j])*f(n/divisors(n)[j]),j=1..tau(n)): for n from 1 to 35 do F:=F union {F[nops(F)]+g(n)} od: G:=sort(convert(F,list)); # _Emeric Deutsch_, Feb 15 2005
%K A101172 easy,nonn
%O A101172 1,2
%A A101172 Mark Hudson (mrmarkhudson(AT)hotmail.com), Dec 03 2004
%E A101172 Corrected and extended by _Emeric Deutsch_, Feb 15 2005
%E A101172 a(33) onward corrected by _Sean A. Irvine_, May 01 2025