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 A344528 #18 Jun 28 2021 10:39:00 %S A344528 0,0,0,2,2,1,5,7,8,5,7,13,14,11,16,31,20,14,19,33,26,26,24,67,43,39, %T A344528 53,62,36,53,40,94,72,48,73,77,64,60,94,122,58,75,68,106,109,81,62, %U A344528 195,114,113,140,151,87,129,143,235,154,97,92,266 %N A344528 a(n) is the number of integer quadrilaterals (up to congruence) with integer side lengths a,b,c,d with n = Max(a,b,c,d) and integer diagonals e,f. %C A344528 This sequence is the sum of the sequences A342720 and A342722 which deal with concave and convex quadrilaterals respectively. %F A344528 a(n) = A342720(n) + A342722(n). %e A344528 a(6)=1 because the only integer quadrilateral with longest edge length 6 is a trapezoid with sides a=6, b=5, c=4, d=5 and diagonals e=f=7. %Y A344528 Cf. A342720, A342721, A342722, A342723, A344529. %K A344528 nonn %O A344528 1,4 %A A344528 _Herbert Kociemba_, May 22 2021