login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A212243 Number of (w,x,y,z) with all terms in {1,...,n} and 2wx+yz=n. 2

%I

%S 0,0,0,1,2,4,7,8,14,13,24,19,33,26,48,32,60,41,75,49,92,58,109,66,127,

%T 76,146,88,168,96,184,106,212,122,227,126,263,140,271,158,304,163,326,

%U 175,363,196,366,198,425,212,416,240,474,238,488,250,528,284

%N Number of (w,x,y,z) with all terms in {1,...,n} and 2wx+yz=n.

%C For a guide to related sequences, see A211795.

%t t = Compile[{{n, _Integer}}, Module[{s = 0},

%t (Do[If[2 w*x + y*z == n, s = s + 1],

%t {w, 1, #}, {x, 1, #}, {y, 1, #}, {z, 1, #}] &[n]; s)]];

%t Map[t[#] &, Range[0, 60]] (* A212243 *)

%t (* _Peter J. C. Moses_, Apr 13 2012 *)

%Y Cf. A211795.

%K nonn

%O 0,5

%A _Clark Kimberling_, May 08 2012

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.

License Agreements, Terms of Use, Privacy Policy. .

Last modified September 28 10:48 EDT 2021. Contains 347714 sequences. (Running on oeis4.)