A138345 a(n) = -1 if (n+1)-st decimal digit of 1/Pi is smaller than n-th digit of 1/Pi, 0 if they are equal, 1 if larger.

-1, 1, -1, -1, 1, -1, 0, -1, -1, 1, -1, 1, 1, -1, 1, 1, -1, 1, -1, 1, 0, -1, 1, -1, -1, 1, 1, -1, 1, -1, 1, 1, -1, -1, 1, -1, 1, 1, 1, -1, 1, -1, 1, -1, 1, 1, -1, 1, -1, 1, 1, 1, -1, -1, 1, -1, -1, 0, 1, 1, 1, 0, -1, 0, 1, 0, 1, -1, 1, 1, -1, -1, 1, 1, -1, 1, -1, -1, 1, -1, 1, 1, -1, 1, 0, 1, -1, -1, 1, 0, -1, -1, 1, -1, 1, -1, 1, -1, 1, -1, 1, -1, 1, 1, 1

Offset: 1

Author

Artur Jasinski, Mar 16 2008

Keywords

• sign
• base

Crossrefs

Cf. A049541, A138344.

Programs

Mathematica

b = RealDigits[N[1/Pi, 1000]]; b = First[b]; a = {}; Do[k = b[[n + 1]] - b[[n]]; If[k < 0, AppendTo[a, -1], If[k == 0, AppendTo[a, 0], AppendTo[a, 1]]], {n, 1, 999}]; a (*Artur Jasinski*)
Which[#[[2]]<#[[1]],-1,#[[2]]==#[[1]],0,True,1]&/@ Partition[ RealDigits[ 1/Pi,10,110][[1]],2,1] (* Harvey P. Dale, Aug 09 2013 *)