This site is supported by donations to The OEIS Foundation.

 Please make a donation to keep the OEIS running. We are now in our 55th year. In the past year we added 12000 new sequences and reached 8000 citations (which often say "discovered thanks to the OEIS"). We need to raise money to hire someone to manage submissions, which would reduce the load on our editors and speed up editing. Other ways to donate

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A292268 Compound filter (multiplicative order of 2 mod 2n+1 & number of trailing 1's in binary expansion of 2n+1): a(n) = P(A002326(n), A007814(2n+2)), where P(n,k) is sequence A000027 used as a pairing function. 4
 1, 5, 10, 13, 21, 65, 78, 25, 36, 189, 21, 89, 210, 189, 406, 41, 55, 90, 666, 103, 210, 119, 78, 348, 231, 44, 1378, 251, 171, 1769, 1830, 61, 78, 2277, 253, 701, 45, 230, 465, 900, 1485, 3485, 36, 463, 66, 90, 55, 816, 1176, 495, 5050, 1429, 78, 5777, 666, 777, 406, 1034, 78, 349, 6105, 230, 5050, 85, 105, 8645, 171, 739, 2346, 9729, 1081 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 LINKS Antti Karttunen, Table of n, a(n) for n = 0..10000 FORMULA a(n) = (1/2)*(2 + ((A002326(n) + A007814(2n+2))^2) - A002326(n) - 3*A007814(2n+2)). PROG (PARI) A002326(n) = if(n<0, 0, znorder(Mod(2, 2*n+1))); \\ This function from Michael Somos, Mar 31 2005 A007814(n) = valuation(n, 2); A292268(n) = (1/2)*(2 + ((A002326(n)+A007814(2*(1+n)))^2) - A002326(n) - 3*A007814(2*(1+n))); (Scheme) (define (A292268 n) (* 1/2 (+ (expt (+ (A002326 n) (A007814 (+ 2 n n))) 2) (- (A002326 n)) (- (* 3 (A007814 (+ 2 n n)))) 2))) CROSSREFS Cf. A000027, A002326, A007814, A292267 (rgs-version of this filter). Cf. also A291755, A292249. Sequence in context: A313448 A313449 A313450 * A309593 A272267 A195735 Adjacent sequences:  A292265 A292266 A292267 * A292269 A292270 A292271 KEYWORD nonn AUTHOR Antti Karttunen, Oct 02 2017 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.

Last modified December 7 05:14 EST 2019. Contains 329839 sequences. (Running on oeis4.)