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 A273929 #20 Sep 08 2022 08:46:17
%S A273929 5,6,7,13,14,15,21,22,23,29,30,31,37,38,39,46,47,53,55,61,62,69,70,71,
%T A273929 77,78,79,85,86,87,93,94,95,101,102,103,109,110,111,118,119,127,133,
%U A273929 134,141,142,143,149,151,157,158,159,165,166,167,173,174
%N A273929 Numbers that are congruent to {5, 6, 7} mod 8 and are squarefree.
%C A273929 It has been shown, conditional on the Birch Swinnerton-Dyer conjecture, that this sequence is a subset of the primitive congruent numbers (A006991). The union of this sequence with A062695 gives A006991. Also this sequence is the intersection of A047574 and A005117.
%C A273929 The asymptotic density of this sequence is 3/Pi^2 (A104141). - _Amiram Eldar_, Mar 09 2021
%H A273929 Keith Conrad, <a href="http://www.math.uconn.edu/~kconrad/articles/congruentnumber.pdf">The Congruent Number Problem</a>, The Harvard College Mathematics Review, 2008.
%t A273929 Select[Range[1000], MemberQ[{5, 6, 7}, Mod[#, 8]] && SquareFreeQ[#] &]
%o A273929 (PARI) is(n) = n % 8 > 4 && issquarefree(n) \\ _Felix Fröhlich_, Jun 04 2016
%o A273929 (Magma) [n: n in [1..250] | n mod 8 in [5, 6, 7] and IsSquarefree(n)]; // _Vincenzo Librandi_, Jun 06 2016
%Y A273929 Cf. A005117, A006991, A047574, A062695, A104141.
%K A273929 nonn
%O A273929 1,1
%A A273929 _Frank M Jackson_, Jun 04 2016