|
Search: id:A000534
|
|
|
| A000534 |
|
Numbers that are not the sum of 4 nonzero squares. |
|
+0
5
|
|
| 0, 1, 2, 3, 5, 6, 8, 9, 11, 14, 17, 24, 29, 32, 41, 56, 96, 128, 224, 384, 512, 896, 1536, 2048, 3584, 6144, 8192, 14336, 24576, 32768, 57344, 98304, 131072, 229376, 393216, 524288, 917504, 1572864, 2097152, 3670016, 6291456, 8388608, 14680064
(list; graph; listen)
|
|
|
OFFSET
|
1,3
|
|
|
REFERENCES
|
J. H. Conway, The Sensual (Quadratic) Form, M.A.A., 1997, p. 140.
|
|
LINKS
|
T. D. Noe, Table of n, a(n) for n=1..100
Index entries for sequences related to sums of squares
|
|
FORMULA
|
Consists of the numbers 0, 1, 3, 5, 9, 11, 17, 29, 41, 2*4^m, 6*4^m and 14*4^m (m >= 0). Compare A123069.
From 224 on, a(n) = 4*a(n-3).
|
|
PROGRAM
|
(PARI) for(n=1, 224, if(sum(a=1, n, sum(b=1, a, sum(c=1, b, sum(d=1, c, if(a^2+b^2+c^2+d^2-n, 0, 1)))))==0, print1(n, ", ")))
(PARI) {a(n)=if(n<1, 0, if(n<15, [1, 2, 3, 5, 6, 8, 9, 11, 14, 17, 24, 29, 32, 41][n], [4, 7, 12][(n+1)%3+1]*2^((n+1)\3*2-7)))} /* Michael Somos Apr 08 2006 */
(PARI) {a(n)=if(n<2, 0, if(n<16, [1, 2, 3, 5, 6, 8, 9, 11, 14, 17, 24, 29, 32, 41][n-1], [4, 7, 12][n%3+1]*2^(n\3*2-7)))} /* Michael Somos Apr 23 2006 */
|
|
CROSSREFS
|
Cf. A123069.
Numbers n such that A025428(n)=0
Essentially the same as A006431.
Sequence in context: A111332 A139791 A027563 this_sequence A136112 A135768 A127936
Adjacent sequences: A000531 A000532 A000533 this_sequence A000535 A000536 A000537
|
|
KEYWORD
|
nonn,easy,nice
|
|
AUTHOR
|
njas and J. H. Conway (conway(AT)math.princeton.edu)
|
|
|
Search completed in 0.002 seconds
|
