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

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A366287 Numbers k such that A163511(k) is a seventh power. 4
 0, 64, 129, 259, 519, 1039, 2079, 4159, 8192, 8319, 16385, 16512, 16639, 32771, 33025, 33152, 33279, 65543, 66051, 66305, 66432, 66559, 131087, 132103, 132611, 132865, 132992, 133119, 262175, 264207, 265223, 265731, 265985, 266112, 266239, 524351, 528415, 530447, 531463, 531971, 532225, 532352, 532479, 1048576, 1048703 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS Equivalently, numbers k for which A332214(k), and also A332817(k) are seventh powers. The sequence is defined inductively as: (a) it contains 0 and 64, and (b) for any nonzero term a(n), (2*a(n)) + 1 and 128*a(n) are also included as terms. When iterating n -> 2n+1 mod 127, starting from 64 we get 64, 2, 5, 11, 23, 47, 95, and then cycle starts again from 64 (see A153893), while on the other hand, x^7 mod 127 obtains values: 0, 1, 19, 20, 22, 24, 28, 37, 52, 59, 68, 75, 90, 99, 103, 105, 107, 108, 126. These sets have no terms in common, therefore there are no seventh powers in this sequence after the initial 0. LINKS Table of n, a(n) for n=1..45. PROG (PARI) A163511(n) = if(!n, 1, my(p=2, t=1); while(n>1, if(!(n%2), (t*=p), p=nextprime(1+p)); n >>= 1); (t*p)); isA366287(n) = ispower(A163511(n), 7); (PARI) isA366287(n) = if(n<=64, !(n%64), if(n%2, isA366287((n-1)/2), if(n%128, 0, isA366287(n>>7)))); CROSSREFS Positions of multiples of 7 in A365805. Sequence A243071(n^7), n >= 1, sorted into ascending order. Cf. A001015, A153893, A163511, A332214, A332817. Cf. A365801, A365802, A365808, A366391. Sequence in context: A031464 A045076 A235058 * A252088 A211254 A252081 Adjacent sequences: A366284 A366285 A366286 * A366288 A366289 A366290 KEYWORD nonn AUTHOR Antti Karttunen, Oct 09 2023 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 September 7 17:00 EDT 2024. Contains 375749 sequences. (Running on oeis4.)