The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A141230 Odd numbers n for which A006694((n-1)/2)=4. 0
 15, 33, 39, 49, 55, 57, 81, 87, 95, 111, 113, 143, 159, 177, 183, 201, 209, 249, 281, 289, 295, 303, 319, 321, 335, 353, 393, 407, 415, 417, 447, 489, 519, 529, 535, 537, 543, 551, 577, 583, 591, 593, 617, 625, 633, 649, 655, 681, 695, 737, 767, 807, 815, 879, 895, 913, 951 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS If p>3 is a prime then 3p is in this sequence if and only if p is in A001122. LINKS PROG (PARI) a006694(n)=sumdiv(2*n+1, d, eulerphi(d)/znorder(Mod(2, d))) - 1; isok(n) = (n % 2) && (a006694((n-1)/2)== 4); \\ Michel Marcus, Dec 18 2018 CROSSREFS Cf. A006694, A001122, A001134. Sequence in context: A064900 A277254 A157137 * A140608 A085371 A162887 Adjacent sequences:  A141227 A141228 A141229 * A141231 A141232 A141233 KEYWORD nonn AUTHOR Vladimir Shevelev, Jun 16 2008 EXTENSIONS More terms from Michel Marcus, Dec 18 2018 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 April 22 19:11 EDT 2021. Contains 343177 sequences. (Running on oeis4.)