This site is supported by donations to The OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A130442 Even pseudoprimes to base 41. 13
 4, 8, 10, 20, 40, 344, 4870, 6892, 17230, 68920, 250820, 296440, 317032, 368722, 369370, 451426, 472312, 473240, 632270, 2326472, 3186730, 3429190, 4438760, 4670956, 4948456, 5509540, 8990356, 11817604, 11841436, 13094342, 17668360 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 LINKS Robert G. Wilson v, Table of n, a(n) for n = 1..146. Eric Weisstein's World of Mathematics, Fermat Pseudoprime. MATHEMATICA Do[ f=PowerMod[ 41, 2n-1, 2n ]; If[ f==1, Print[ 2n ] ], {n, 2, 500000} ] lst = {}; Do[ If[ PowerMod[41, 2n - 1, 2n] == 1, AppendTo[lst, 2n]], {n, 2, 2^31}]; lst (* Robert G. Wilson v, Jun 01 2007 *) CROSSREFS Cf. A020169 = Pseudoprimes to base 41. Cf. A006935 = Even pseudoprimes (or primes) to base 2: n divides 2^n - 2, n even. Cf. A130433 = Even pseudoprimes to base 3. Cf. A090082 = Even pseudoprimes to base 5. Cf. A090083, A090084, A090085. Cf. A130434, A130435, A130436, A130437, A130438, A130439, A130440, A130441, A130443. Cf. A020169, A006935, A130433, A090082, A090083, A090084, A090085, A130434, A130435, A130436, A130437, A130438, A130439, A130440, A130441, A130443. Sequence in context: A090696 A048247 A276607 * A031073 A037004 A136861 Adjacent sequences:  A130439 A130440 A130441 * A130443 A130444 A130445 KEYWORD nonn AUTHOR Alexander Adamchuk, May 26 2007 EXTENSIONS More terms from Robert G. Wilson v, Jun 01 2007 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 | More pages
The OEIS Community | Maintained by The OEIS Foundation Inc.