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 A353448 #50 Jun 16 2022 16:40:05
%S A353448 3,4,5,7,10,11,13,14,15,16,17,19,21,23,25,29,31,33,34,37,41,43,45,46,
%T A353448 49,55,57,61,67,73,79,81,85,89,91,97,109,113,121,127,133,141,145,151,
%U A353448 157,161,169,181,193,201,205,209,211,217,221,225,241,253,261,265,271
%N A353448 Number w is in this sequence if every frame w X h, w >= h >= 3, contains more distinct distance quadrilaterals with corners interior to the 4 sides with concurrent diagonals, i.e., both ascending or both descending, than non-concurrent diagonals, or equivalently A353450(w,h) >= A353449(w,h).
%C A353448 It is conjectured that this sequence is a subsequence A160007 except for the small terms <= 46 (verified for all w < 661). The example section depicts the way this sequence matches the irregular pattern of A160007. Numbers w > 100 were computed by _Hugo Pfoertner_.
%C A353448 w = 617 is one of the rare occurrences of remainder 17 mod 60 in A160007, and it is also in this sequence. One might suspect that there would be less and less hits, but the time-consuming computation successfully countered the intuition.
%H A353448 Rainer Rosenthal, <a href="/A353448/b353448.txt">Table of n, a(n) for n = 1..96</a>
%H A353448 Hugo Pfoertner, <a href="https://oeis.org/plot2a?name1=A225730&name2=A353448&tform1=untransformed&tform2=untransformed&shift=0&radiop1=matp&drawpoints=true">Comparison to A225730</a>, using Plot 2.
%e A353448 .
%e A353448 w = 5 is in this sequence:
%e A353448 .
%e A353448 5 | . . . C .
%e A353448 4 | . . C . . 4 | . . w = 5 is in this sequence because all
%e A353448 3 | . B 3 | . B quadrilaterals in (5,4) and (5,5)
%e A353448 2 | D . 2 | D . shown in the example section of A353450
%e A353448 1 | . A . . . 1 | . A . . . have concurrent diagonals.
%e A353448 y /---------- y /----------
%e A353448 x 1 2 3 4 5 x 1 2 3 4 5
%e A353448 .
%e A353448 w = 6 is *not* in this sequence:
%e A353448 .
%e A353448 4 | . . . C . . w = 6 is not in this sequence because of the single
%e A353448 3 | D . quadrilateral in (6,4) shown in the example section
%e A353448 2 | . B of A353449. Diagonal AC is rising while diagonal DB
%e A353448 1 | . A . . . . is falling (non-concurrent diagonals).
%e A353448 y /------------ There is no (6,4) quadrilateral with all distances
%e A353448 x 1 2 3 4 5 6 distinct and with concurrent diagonals!
%e A353448 .
%e A353448 123456789012345678901234567890123456789012345678901234567890
%e A353448 1 - 60 ::: x :: x:::: x x : x x x :: x x x :: x x x
%e A353448 61 - 120 x x . x x x x x x x . . . x x .
%e A353448 121 - 180 x x x . x x x x x . x . .
%e A353448 181 - 240 x . x . . x x x x x x . x . .
%e A353448 241 - 300 x . x . x x x . . x . x .
%e A353448 301 - 360 x . . . x . x x . x . . . . . .
%e A353448 361 - 420 x . . . . x . x x . x x . x . .
%e A353448 421 - 480 x . x . x . . . x . x . x . .
%e A353448 481 - 540 x . . . . . . x . . x . x . .
%e A353448 541 - 600 x . . . . . x . . . x . . x .
%e A353448 601 - 660 x . . x x . . x x . x . . x . .
%e A353448 .
%e A353448 Legend:
%e A353448 "x" marks numbers w belonging to this sequence and to A160007.
%e A353448 ":" marks numbers w belonging to this sequence only.
%e A353448 "." marks numbers w belonging to A160007 only.
%Y A353448 Cf. A160007, A353532 ("all tetrapods"), A353449 ("unisense"), A353450 ("contrasense").
%Y A353448 Cf. A225730 (has many terms in common when 1 is added, see also comparison plot).
%K A353448 nonn
%O A353448 1,1
%A A353448 _Rainer Rosenthal_, May 22 2022