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 A022090 #39 Apr 10 2025 06:52:11 %S A022090 0,7,7,14,21,35,56,91,147,238,385,623,1008,1631,2639,4270,6909,11179, %T A022090 18088,29267,47355,76622,123977,200599,324576,525175,849751,1374926, %U A022090 2224677,3599603,5824280,9423883,15248163,24672046,39920209,64592255,104512464 %N A022090 Fibonacci sequence beginning 0, 7. %C A022090 The number of heptagons in the n-th ring of the Klein Quartic. - _Amiram Eldar_, Nov 14 2023 %D A022090 Arthur T. Benjamin and Jennifer J. Quinn, Proofs that really count: the art of combinatorial proof, M.A.A., 2003, p. 15. %H A022090 G. C. Greubel, <a href="/A022090/b022090.txt">Table of n, a(n) for n = 0..1000</a> %H A022090 Tanya Khovanova, <a href="http://www.tanyakhovanova.com/RecursiveSequences/RecursiveSequences.html">Recursive Sequences</a>. %H A022090 William P. Thurston, <a href="https://people.eecs.berkeley.edu/~sequin/CS285/PAPERS/thurston.pdf">The Eightfold Way: A Mathematical Sculpture by Helaman Ferguson</a>, in: The Eightfold Way: The Beauty of the Klein Quartic (ed. Silvio Levy), Cambridge University Press, New York, 1999, pp. 1-7. %H A022090 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/KleinQuartic.html">Klein Quartic</a>. %H A022090 <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (1,1). %F A022090 a(n) = round(((14*phi-7)/5) * phi^n), for n>3. - _Thomas Baruchel_, Sep 08 2004 %F A022090 a(n) = 7*Fibonacci(n) = Fibonacci(n+4) + Fibonacci(n-4) for n>3. %F A022090 a(n) = A119457(n+5, n-1) for n>1. - _Reinhard Zumkeller_, May 20 2006 %F A022090 G.f.: 7*x/(1-x-x^2). - _Philippe Deléham_, Nov 20 2008 %t A022090 7*Fibonacci[Range[0,40]] (* _Vladimir Joseph Stephan Orlovsky_, Jul 23 2008 *) %o A022090 (Magma) %o A022090 A022090:= func< n | 7*Fibonacci(n) >; [A022090(n): n in [0..40]]; // _G. C. Greubel_, Apr 10 2025 %o A022090 (SageMath) %o A022090 def A022090(n): return 7*fibonacci(n) %o A022090 [A022090(n) for n in range(41)] # _G. C. Greubel_, Apr 10 2025 %Y A022090 Cf. A000032, A000045, A001622, A119457. %Y A022090 Sequences of the form Fibonacci(n+k) + Fibonacci(n-k) are listed in A280154. %Y A022090 Sequences of the form m*Fibonacci are listed in A022086. %K A022090 nonn,easy %O A022090 0,2 %A A022090 _N. J. A. Sloane_