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

 Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 60th year, we have over 367,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”). Other ways to Give
 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A199398 XOR of the first n odd numbers. 2
 1, 2, 7, 0, 9, 2, 15, 0, 17, 2, 23, 0, 25, 2, 31, 0, 33, 2, 39, 0, 41, 2, 47, 0, 49, 2, 55, 0, 57, 2, 63, 0, 65, 2, 71, 0, 73, 2, 79, 0, 81, 2, 87, 0, 89, 2, 95, 0, 97, 2, 103, 0, 105, 2, 111, 0, 113, 2, 119, 0, 121, 2, 127, 0, 129, 2, 135, 0, 137, 2, 143, 0, 145, 2, 151, 0, 153, 2, 159, 0, 161, 2, 167, 0, 169, 2, 175, 0, 177, 2, 183, 0, 185, 2, 191 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 LINKS Indranil Ghosh, Table of n, a(n) for n = 1..25000 FORMULA G.f.: x*(1 + 2*x + 6*x^2 - 2*x^3 + x^4)/((1-x^2)*(1-x^4)). EXAMPLE a(2) = 1 XOR 3 = 2; a(3) = 1 XOR 3 XOR 5 = 7; a(4) = 1 XOR 3 XOR 5 XOR 7 = 0. MAPLE a := proc(n) local u, b, w, k; u := 1; w := 1; b := true; for k from 2 to n do u := u + 2; w := u + `if`(b, -w, +w); b := not b; od; w end: seq(a(n), n=1..95); # Peter Luschny, Dec 31 2014 MATHEMATICA With[{c=Range[1, 201, 2]}, Table[BitXor@@Take[c, n], {n, 100}]] (* Harvey P. Dale, Nov 19 2011 *) PROG (PARI) a(n)=if(n==1, 1, bitxor(a(n-1), 2*n-1)) (PARI) Vec((1 + 2*x + 6*x^2 - 2*x^3 + x^4)/(1-x^2)/(1-x^4)+O(x^99)) \\ Charles R Greathouse IV, Dec 31 2014 (Python) from operator import xor from functools import reduce def A199398(n): return reduce(xor, range(1, n<<1, 2)) # Chai Wah Wu, Jul 09 2022 CROSSREFS Cf. A126084 (XOR of first n primes). Sequence in context: A196833 A245224 A016638 * A296453 A081544 A011294 Adjacent sequences: A199395 A199396 A199397 * A199399 A199400 A199401 KEYWORD nonn,easy AUTHOR Paul D. Hanna, Nov 05 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 December 7 02:45 EST 2023. Contains 367622 sequences. (Running on oeis4.)