cp's OEIS Frontend

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.

A086767 Last coefficient of the last term in the numerator of the simplified expansion of the solutions of FLT for n=2 for FLT n=1,2,3,..

Original entry on oeis.org

1, 1, 1, 1, 1, 3, 1, 1, 1, 5, 1, 3, 1, 7, 1, 1, 1, 9, 1, 5, 1, 11, 1, 3, 1, 13, 1, 7, 1, 15, 1, 1, 1, 17, 1, 9, 1, 19, 1, 5, 1, 21, 1, 11, 1, 23, 1, 3, 1, 25, 1, 13, 1, 27, 1, 7, 1, 29, 1, 15, 1, 31, 1, 1, 1, 33, 1, 17, 1, 35, 1, 9, 1, 37, 1, 19, 1, 39, 1, 5, 1, 41, 1, 21, 1, 43, 1, 11, 1, 45, 1, 23
Offset: 0

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Author

Cino Hilliard, Aug 02 2003

Keywords

Comments

Integers a > b form the solution to FLT n = 2 as follows. (2ab)^2 = (a^2-b^2)^2 - (a^2+b^2)^2. The sequence is the coefficient c of the last b term in the numerator for the simplified expansion of the solution for n=2 as verification of FLT for n=1, 2, ...

Examples

			b/a
1
(3*a^4 + b^4)/(4*b*a^3)
(a^4 + b^4)/(2*b^2*a^2)
(5*a^8 + 10*b^4*a^4 + b^8)/(16*b^3*a^5)
(3*a^8 + 10*b^4*a^4 + 3*b^8)/(16*b^4*a^4)
(7*a^12 + 35*b^4*a^8 + 21*b^8*a^4 + b^12)/(64*b^5*a^7)
(a^12 + 7*b^4*a^8 + 7*b^8*a^4 + b^12)/(16*b^6*a^6)
(9*a^16 + 84*b^4*a^12 + 126*b^8*a^8 + 36*b^12*a^4 + b^16)/(256*b^7*a^9)
(5*a^16 + 60*b^4*a^12 + 126*b^8*a^8 + 60*b^12*a^4 + 5*b^16)/(256*b^8*a^8)
........
(K + cb^m)/2^m1b^m2c^m3
Seq = c for integers K,b,m1,m2,m3,n = 1,2,3...
		

Crossrefs

Programs

  • Maple
    sigma := proc(n) local i; add(i,i=convert(n,base,2)) end:
    a := proc(n) if n=0 or type(n,odd) then 1 else if type(iquo(n,2),odd) then n/2 else n/2^(1-sigma(n)+sigma(n-1)) fi fi end: # Peter Luschny, Aug 03 2009
  • PARI
    \ verification of general solution in integers \ a>b,x = 2ab,y=a^2-b^2,z=a^2+b^2 \ or FLT n=2 x^n+y^n <> z^n = (2ab)^n + (a^2-b^2)^n <> \(a^2+b^2)^n for n > 2 flt(n,a1,b1) = for(x=0,n,print(f(x,a1,b1))) f(n,a,b) = simplify(((a^2+b^2)^n - (a^2-b^2)^n)/(2*a*b)^n) coeffb(m) = { for(y=1,m, n=y; if(n%2,x=1, while(n%2==0,n=n/2); x=n; ); print1(x",") ) }

Formula

a(n) = A004731(n+1)/A004730(n). - Flávio V. Fernandes, Feb 13 2025