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 A202503 #20 Jan 05 2025 19:51:39 %S A202503 1,1,2,2,3,3,3,5,5,5,5,8,9,8,8,8,13,14,15,13,13,13,21,23,24,24,21,21, %T A202503 21,34,37,39,39,39,34,34,34,55,60,63,64,63,63,55,55,55,89,97,102,103, %U A202503 104,102,102,89,89,89,144,157,165,167,168,168,165,165,144,144,144 %N A202503 Fibonacci self-fission matrix, by antidiagonals. %C A202503 The Fibonacci self-fission matrix, F, is the fission P^^Q, where P and Q are the matrices given at A202502 and A202451. See A193842 for the definition of fission. %C A202503 antidiagonal sums: (1, 3, 8, 18, 38, ...), A064831 %C A202503 diagonal (1, 5, 14, 39, ...), A119996 %C A202503 diagonal (2, 8, 23, 63, ...), A180664 %C A202503 diagonal (2, 5, 15, 39, ...), A059840 %C A202503 diagonal (3, 8, 24, 63, ...), A080097 %C A202503 diagonal (5, 13, 39, 102, ...), A080143 %C A202503 diagonal (8, 21, 63, 165, ...), A080144 %C A202503 All the principal submatrices are invertible, and the terms in the inverses are in {-3,-2,-1,0,1,2,3}. %H A202503 Clark Kimberling, <a href="https://web.archive.org/web/2024*/https://www.fq.math.ca/Papers1/52-3/Kimberling11132013.pdf">Fusion, Fission, and Factors</a>, Fib. Q., 52 (2014), 195-202. %e A202503 Northwest corner: %e A202503 1....1....2....3....5.....8....13...21 %e A202503 2....3....5....8...13....21....34...55 %e A202503 3....5....9...14...23....37....60...97 %e A202503 5....8...15...24...39....63...102...165 %e A202503 8...13...24...39...64...103...167...270 %t A202503 n = 14; %t A202503 Q = NestList[Most[Prepend[#, 0]] &, #, Length[#] - 1] &[Table[Fibonacci[k], {k, 1, n}]]; %t A202503 Qt = Transpose[Q]; P1 = Qt - IdentityMatrix[n]; %t A202503 P = P1[[Range[2, n], Range[1, n]]]; %t A202503 F = P.Q; %t A202503 Flatten[Table[P[[i]][[k + 1 - i]], {k, 1, n - 1}, {i, 1, k}]] (* A202502 as a sequence *) %t A202503 Flatten[Table[Q[[i]][[k + 1 - i]], {k, 1, n - 1}, {i, 1, k}]] (* A202451 as a sequence *) %t A202503 Flatten[Table[F[[i]][[k + 1 - i]], {k, 1, n - 1}, {i, 1, k}]] (* A202503 as a sequence *) %t A202503 TableForm[P] (* A202502, modified lower triangular Fibonacci array *) %t A202503 TableForm[Q] (* A202451, upper tri. Fibonacci array *) %t A202503 TableForm[F] (* A202503, Fibonacci fission array *) %Y A202503 Cf. A000045, A202451, A202453, A202502. %K A202503 nonn,tabl %O A202503 1,3 %A A202503 _Clark Kimberling_, Dec 20 2011