login

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).

a(n) = max{ C(n,0), C(n-1,1), C(n-2,2), ..., C(n-n,n) }.
7

%I #38 Oct 27 2022 09:34:58

%S 1,1,1,2,3,4,6,10,15,21,35,56,84,126,210,330,495,792,1287,2002,3003,

%T 5005,8008,12376,19448,31824,50388,77520,125970,203490,319770,497420,

%U 817190,1307504,2042975,3268760,5311735,8436285,13123110,21474180,34597290

%N a(n) = max{ C(n,0), C(n-1,1), C(n-2,2), ..., C(n-n,n) }.

%C lim a(n)/a(n-1) = (1+sqrt(5))/2.

%C a(n-1) is the max coefficient in n-th Fibonacci polynomial (the polynomial F_0(x) is constant zero, and is not included in this sequence). - _Vladimir Reshetnikov_, Oct 09 2016

%D Peter Boros (borospet(AT)freemail.hu): Lectures on Fibonacci's World at the SOTERIA Foundation, 1999.

%H Charles R Greathouse IV, <a href="/A073028/b073028.txt">Table of n, a(n) for n = 0..4793</a>

%H Benjamin Aram Berendsohn, László Kozma, and Dániel Marx, <a href="https://arxiv.org/abs/1908.04673">Finding and counting permutations via CSPs</a>, arXiv:1908.04673 [cs.DS], 2019.

%H Charles Bouillaguet, <a href="https://eprint.iacr.org/2022/1412.pdf">Boolean Polynomial Evaluation for the Masses</a>, LIP6 Laboratory, Sorbonne Université (Paris, France) Cryptology ePrint Archive (2022) No. 1412.

%H S. M. Tanny and M. Zuker, <a href="http://dx.doi.org/10.1016/0012-365X(74)90073-9">On a unimodal sequence of binomial coefficients</a>, Discrete Math. 9 (1974), 79-89.

%H Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/FibonacciPolynomial.html">Fibonacci Polynomial</a>.

%F a(n) = binomial(n-A060065(n), A060065(n)). - _Vladeta Jovovic_, Jun 16 2004

%F a(n) ~ 5^(1/4) * phi^(n+1) / sqrt(2*Pi*n), where phi = A001622 = (1+sqrt(5))/2 is the golden ratio. - _Vaclav Kotesovec_, Oct 09 2016

%e For n = 6, C(6,0) = 1, C(5,1) = 5, C(4,2) = 6, C(3,3) = 1. These binomial coefficients are the coefficients in the Fibonacci polynomial F_7(x) = x^6 + 5*x^4 + 6*x^2 + 1. The max coefficient is 6, so a(6) = 6.

%t Table[Max[CoefficientList[Fibonacci[n + 1, x], x]], {n, 1, 30}] (* _Vladimir Reshetnikov_, Oct 07 2016 *)

%o (PARI) a(n)=my(k=(5*n-sqrtint(5*n^2+10*n+9)+6)\10); binomial(n-k,k) \\ _Charles R Greathouse IV_, Sep 22 2016

%Y Cf. A060065, A277282, A168561.

%K easy,nonn

%O 0,4

%A _Miklos Kristof_, Aug 22 2002

%E a(0) = 1 prepended by _Vladimir Reshetnikov_, Oct 09 2016