cp's OEIS Frontend

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.

A111198 Numbers k such that sequence A_k does not contain a perfect square.

This page as a plain text file.
%I A111198 #20 Jun 26 2025 15:34:25
%S A111198 37,40,43,57,58,101
%N A111198 Numbers k such that sequence A_k does not contain a perfect square.
%C A111198 That is, the complete sequence A_k, not just the terms that are shown in the entry, does not contain a perfect square or the negative of a perfect square. (In particular, sequences containing 0 or 1 are excluded.)
%C A111198 No more terms up through 130. Does A000131 contain a perfect square?
%C A111198 I've checked A000131 up to a(25000) and can report that I found no perfect square. - _Robert G. Wilson v_, Jun 23 2014
%H A111198 <a href="/index/Se#selfies">Index entries for sequences whose definition involves A_n (or An)</a>.
%e A111198 The first term, 37, refers to the sequence A000037, the nonsquares. All of A000001-A000036 contain obvious square terms.
%e A111198 The second term, 40, refers to A000040, the primes. Obviously any sequence which is a subset of the primes (e.g. A000043) also gives a term.
%K A111198 nonn,dumb,less
%O A111198 1,1
%A A111198 _Zak Seidov_, Oct 24 2005
%E A111198 Let's have no more sequences of this type! - _N. J. A. Sloane_, Oct 23 2005