A080390 Least x such that gcd(A001405(x+1), A001405(x)) = n.

1, 5, 14, 27, 34, 11, 62, 183, 98, 39, 142, 107, 220, 69, 44, 495, 322, 143, 436, 139, 482, 637, 574, 119, 674, 233, 782, 55, 898, 29, 1146, 4063, 230, 441, 174, 467, 1516, 493, 662, 239, 1762, 377, 2020, 175, 764, 781, 2302, 2543, 2596, 949, 968, 207, 3126, 1241

Offset

1,2

Links

Table of n, a(n) for n=1..54.

Formula

a(n) = Min{x; A057977(x)=n}.

Mathematica

f[x_] := GCD[Binomial[x+1, Floor[x+1/2]], Binomial[x, Floor[x/2]]] t=Table[0, {257}]; Do[s=f[n]; If[s<258&&t[[s]]==0, t[[s]]=n], {n, 1, 10000}]; t

Crossrefs

Cf. A001405, A057977, A080389.

Sequence in context: A301689 A367690 A066479 * A030745 A071421 A185233

Adjacent sequences: A080387 A080388 A080389 * A080391 A080392 A080393

Keyword

nonn

Author

Labos Elemer, Mar 12 2003

Status

approved