The OEIS is supported by the many generous donors to the OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A087414 Numbers n such that 2*n*k(n) is rational but not an integer, where k(n) is sum of successive remainders when computing the Euclidean algorithm for (1, 1/sqrt(n)) as defined in A086378 (MuPAD program is given there); numbers belonging to A086378 but not to A088900. 0
 153, 1717, 2244, 2340, 3525, 3650, 6460, 7119, 7475, 10074, 14490, 19147, 20008, 20862, 21424, 21747, 24453, 25400, 26039, 27346, 28028, 28371, 31484, 35483, 37008, 44275, 44678, 45974, 50389, 52155, 62187, 63724, 64752 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 LINKS PROG (PARI) /* z(n)!=0 iff n is in the sequence */ z(n)= { local(a, b, c, d, e, f, g, h, i, j, k); b=a=sqrtint(n); d=f=i=1; e=g=h=0; j=c=n-a^2; if(!c, return(0)); until((a==b)&&(c==j), k=d+a*e; f*=c; d=a*d+e*n; e=k; g+=i; i*=c; k=g+a*h; g=a*g+h*n; h=k; k=(a+b)\c; g-=i*k; a=c*k-a; c=(n-a^2)/c); d=d/f-1; e/=f; g/=i; h/=i; i=d^2-n*e^2; k=h*d-g*e; g=g*d-h*e*n; b=n-a^2; a=b*g-c*a*i; c=b*k+i*c; b*=i; !a*(2%(b/gcd(b, n*c))); } CROSSREFS Cf. A086378 and A088900. Sequence in context: A050209 A109142 A014576 * A184369 A073938 A278285 Adjacent sequences: A087411 A087412 A087413 * A087415 A087416 A087417 KEYWORD nonn AUTHOR Thomas Baruchel, Oct 21 2003 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified January 27 12:24 EST 2023. Contains 359840 sequences. (Running on oeis4.)