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

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A155816 First nonzero digit in the decimal expansion of (cos Pi/4)^n. 1
 7, 5, 3, 2, 1, 1, 8, 6, 4, 3, 2, 1, 1, 7, 5, 3, 2, 1, 1, 9, 6, 4, 3, 2, 1, 1, 8, 6, 4, 3, 2, 1, 1, 7, 5, 3, 2, 1, 1, 9, 6, 4, 3, 2, 1, 1, 8, 5, 4, 2, 2, 1, 1, 7, 5, 3, 2, 1, 1, 9, 6, 4, 3, 2, 1, 1, 8, 5, 4, 2, 2, 1, 1, 7, 5, 3, 2, 1, 1, 9, 6, 4, 3, 2, 1, 1 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 LINKS Robert Israel, Table of n, a(n) for n = 1..10000 FORMULA a(2*k) = A111395(k). - Robert Israel, Aug 22 2023 EXAMPLE (cos Pi/4)^4=0.25, so a(4)=2. (cos Pi/4)^8=0.0625, so a(8)=6. MAPLE f:= proc(n) local t, m; m:= 1 + ilog10(floor(2^(n/2))); floor(10^m * 2^(-n/2)) end proc: map(f, [\$1..100]); # Robert Israel, Aug 22 2023 MATHEMATICA With[{c=Cos[Pi/4]}, Table[First[RealDigits[N[c^n, 20]][[1]]], {n, 120}]] (* Harvey P. Dale, Nov 07 2012 *) CROSSREFS Cf. A111395. Sequence in context: A180597 A219242 A330920 * A308414 A360895 A335985 Adjacent sequences: A155813 A155814 A155815 * A155817 A155818 A155819 KEYWORD nonn,base AUTHOR Avik Roy (avik_3.1416(AT)yahoo.co.in), Jan 28 2009 EXTENSIONS More terms from Harvey P. Dale, Nov 07 2012 Offset corrected by Robert Israel, Aug 22 2023 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 November 28 14:42 EST 2023. Contains 367419 sequences. (Running on oeis4.)