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

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A199889 Number of compositions of n such that the number of parts and the smallest part are not coprime. 3
 0, 0, 0, 1, 2, 2, 2, 4, 9, 17, 30, 49, 76, 116, 180, 286, 460, 746, 1217, 1990, 3251, 5303, 8639, 14057, 22844, 37077, 60110, 97356, 157568, 254920, 412387, 667212, 1079754, 1747807, 2829756, 4582021, 7419619, 12014143, 19452288, 31492382, 50979547, 82517631 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,5 LINKS Alois P. Heinz, Table of n, a(n) for n = 1..500 FORMULA a(n) = A000079(n-1) - A199888(n). a(n) ~ 1/(2*sqrt(5)) * ((1+sqrt(5))/2)^(n-1). - Vaclav Kotesovec, May 01 2014 EXAMPLE a(8) = 4: [2,2,2,2], [2,6], [4,4], [6,2]. MAPLE b:= proc(n, t, g) option remember; `if`(n=0, `if`(igcd(g, t)<>1, 1, 0), add(b(n-i, t+1, min(i, g)), i=1..n)) end: a:= n-> b(n, 0, infinity): seq(a(n), n=1..50); MATHEMATICA b[n_, t_, g_] := b[n, t, g] = If[n == 0, If[GCD[g, t] != 1, 1, 0], Sum[b[n-i, t+1, Min[i, g]], {i, 1, n}]]; a[n_] := b[n, 0, Infinity]; Table[a[n], {n, 1, 40}] (* Jean-François Alcover, Nov 05 2014, after Alois P. Heinz *) CROSSREFS Cf. A000079, A199888, A201025. Sequence in context: A160179 A021822 A153986 * A293177 A231382 A360314 Adjacent sequences: A199886 A199887 A199888 * A199890 A199891 A199892 KEYWORD nonn AUTHOR Alois P. Heinz, Nov 11 2011 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 29 16:16 EST 2023. Contains 367445 sequences. (Running on oeis4.)