The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation. Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A127264 Nearest integer to 2*(Sum_{i=1..10^n/2} 1/i) - 1. 1
 4, 8, 13, 17, 22, 26, 31, 36, 40, 45, 49, 54, 59, 63, 68, 72, 77, 82, 86, 91, 95, 100, 105, 109, 114, 119, 123, 128, 132, 137, 142, 146, 151, 155, 160, 165, 169, 174, 178, 183, 188, 192, 197, 201, 206, 211, 215, 220, 224, 229, 234, 238, 243, 247, 252, 257, 261, 266, 270, 275 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS The original definition was: Nearest integer to Sum[(10^n-i)/i,{i,1,10^n/2}]/(10^n/2), but this was simplified to the present definition by Jon E. Schoenfield, Aug 05 2008. LINKS Jon E. Schoenfield, Table of n, a(n) for n = 1..1000 FORMULA a(n) = round(2 * (log(m) + Gamma) + 1/m - ...) - 1 where m = 10^n / 2 and Gamma = 0.57721566490153286... (the Euler-Mascheroni constant A001620). - Jon E. Schoenfield, Aug 05 2008 EXAMPLE a(1)=4 because round((9/1 + 8/2 + 7/3 + 6/4 + 5/5)/5) is 4. a(2)=8 because round((99/1 + 98/2 + ... + 50/50))/50 is 8. MAPLE for i from 10 to 11 by 2 do s:=0; t:=0; for d from i/2 to i -1 do s:= s + (d / (i - d)); t:= t +1; end do; print(round((s / t))); end do; MATHEMATICA Table[Round[-1 + 2*HarmonicNumber[Floor[10^n/2]]], {n, 1, 50}] (* G. C. Greubel, Aug 31 2018 *) PROG (PARI) a(n)={ my(i, a=0); for(i=1, 10^n/2, a += 1/i); return(round(2*a-1)); } main(size)={return(vector(size, m, a(m))); } /* Anders Hellström, Jul 12 2015 */ CROSSREFS Different from A004081, although the sequences have the same first few terms. Sequence in context: A311935 A311936 A004081 * A311937 A311938 A311939 Adjacent sequences:  A127261 A127262 A127263 * A127265 A127266 A127267 KEYWORD nonn AUTHOR Ben Paul Thurston, Mar 27 2007 EXTENSIONS Extended and edited by John W. Layman, Jul 10 2007 Terms from a(11) onwards from Jon E. Schoenfield, Aug 05 2008 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified October 17 00:35 EDT 2021. Contains 348048 sequences. (Running on oeis4.)