login
This site is supported by donations to The OEIS 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
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, 76, 146, 88, 168, 96, 184, 106, 212, 122, 227, 126, 263, 140, 271, 158, 304, 163, 326, 175, 363, 196, 366, 198, 425, 212, 416, 240, 474, 238, 488, 250, 528, 284 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,5

COMMENTS

For a guide to related sequences, see A211795.

LINKS

Table of n, a(n) for n=0..57.

MATHEMATICA

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

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

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

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

(* Peter J. C. Moses, Apr 13 2012 *)

CROSSREFS

Cf. A211795.

Sequence in context: A018614 A176745 A287208 * A306235 A004616 A322386

Adjacent sequences:  A212240 A212241 A212242 * A212244 A212245 A212246

KEYWORD

nonn

AUTHOR

Clark Kimberling, May 08 2012

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.

License Agreements, Terms of Use, Privacy Policy. .

Last modified November 17 06:06 EST 2019. Contains 329217 sequences. (Running on oeis4.)