|
| |
|
|
A145768
|
|
a(n) = the bitwise XOR of squares of first n natural numbers
|
|
7
| |
|
|
0, 1, 5, 12, 28, 5, 33, 16, 80, 1, 101, 28, 140, 37, 225, 0, 256, 33, 357, 12, 412, 37, 449, 976, 400, 993, 325, 924, 140, 965, 65, 896, 1920, 961, 1861, 908, 1692, 965, 1633, 912, 1488, 833, 1445, 668, 1292, 741, 2721, 512, 2816, 609, 2981, 396, 2844, 485
(list; graph; refs; listen; history; internal format)
|
|
|
|
OFFSET
| 0,3
|
|
|
COMMENTS
| Up to n=10^8, a(15) is the only zero term and a(1)=a(9) are the only terms for which a(n)=1. Can it be proved that any number can only appear a finite number of times in this sequence? [From M. F. Hasler (www.univ-ag.fr/~mhasler), Oct 20 2008]
|
|
|
FORMULA
| a(n)=1^2 xor 2^2 xor ... xor n^2
|
|
|
MATHEMATICA
| Rest@ FoldList[BitXor, 0, Array[#^2 &, 50]]
|
|
|
PROG
| (PARI) an=0; for( i=1, 50, print1(an=bitxor(an, i^2), ", ")) [From M. F. Hasler (www.univ-ag.fr/~mhasler), Oct 20 2008]
(PARI) al(n)=local(m); vector(n, k, m=bitxor(m, k^2))
|
|
|
CROSSREFS
| Cf. A003815, A145827-A145829, A145830-A145831. [From M. F. Hasler (www.univ-ag.fr/~mhasler), Oct 20 2008]
Cf. A193232.
Sequence in context: A170828 A128439 A172426 * A162778 A160807 A038376
Adjacent sequences: A145765 A145766 A145767 * A145769 A145770 A145771
|
|
|
KEYWORD
| easy,nonn
|
|
|
AUTHOR
| Vladimir Reshetnikov (v.reshetnikov(AT)gmail.com), Oct 18 2008
|
| |
|
|
