A076587 First occurrence of n as a term in the continued fraction for Pi/2.

1, 10, 4, 9, 20, 13, 26, 11, 142, 102, 70, 93, 179, 69, 127, 283, 52, 1166, 141, 605, 100, 83, 280, 414, 451, 61, 30, 234, 848, 448, 5, 372, 1389, 2445, 2082, 498, 603, 2565, 517, 3715, 22, 1155, 419, 856, 4125, 1573, 441, 207, 42, 1536, 5359, 576, 6654, 1002

Offset: 1

Author

Benoit Cloitre, Oct 20 2002

Keywords

• base
• nonn

Crossrefs

Cf. A032523, A053300.

Programs

Mathematica

Module[{nn=6700,p2},p2=ContinuedFraction[Pi/2,nn];Table[Position[p2,n,1,1],{n,60}]]//Flatten (* Harvey P. Dale, Jul 14 2023 *)

PARI

default(realprecision, 1500); v=contfrac(Pi/2); a(n)=if(n<0,0,s=1; while(abs(n-component(v,s))>0,s++); s)