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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

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