A137994 a(n) is the smallest integer > a(n-1) such that {Pi^a(n)} < {Pi^a(n-1)}, where {x} = x - floor(x), a(1)=1.

1, 3, 81, 264, 281, 472, 1147, 2081, 3207, 3592, 10479, 12128, 65875, 114791, 118885

Offset

1,2

Comments

The sequence was suggested by Leroy Quet on Pi day 2008, cf. A138324.

The next such number must be greater than 100000. [Hieronymus Fischer, Jan 06 2009]

a(16) > 300,000. - Robert Price, Mar 25 2019

Links

Table of n, a(n) for n=1..15.

Example

a(3)=81, since fract((Pi^81)=0.0037011283.., but fract(Pi^k)>=0.0062766802... for 1<=k<=80; thus fract(Pi^81)<fract(Pi^k) for 1<=k<81. [Hieronymus Fischer, Jan 06 2009]

Mathematica

$MaxExtraPrecision = 10000;
p = .999;
Select[Range[1, 5000],
If[FractionalPart[Pi^#] < p, p = FractionalPart[Pi^#]; True] &] (* Robert Price, Mar 12 2019 *)

Prog

(PARI) default(realprecision, 10^4); print1(a=1); for(i=1, 100, f=frac(Pi^a); until( frac(Pi^a++)<f, ); print1(", "a))

Crossrefs

Cf. A001203, A138324, A001672.

Cf. A081464, A153669, A153677, A153685, A153693, A153705, A153713, A154130, A153717 [Hieronymus Fischer, Jan 06 2009]

Sequence in context: A251694 A355626 A274567 * A074386 A116009 A068562

Adjacent sequences: A137991 A137992 A137993 * A137995 A137996 A137997

Keyword

nonn,more

Author

Leroy Quet and M. F. Hasler, Mar 14 2008

Extensions

a(11)-a(13) from Hieronymus Fischer, Jan 06 2009

Edited by R. J. Mathar, May 21 2010

a(14)-a(15) from Robert Price, Mar 12 2019

Status

approved