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

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A324392 a(n) is the number of divisors d of n such that A000120(d) divides n, where A000120(d) gives the binary weight of d. 2
 1, 2, 1, 3, 1, 4, 1, 4, 1, 4, 1, 6, 1, 2, 1, 5, 1, 6, 1, 6, 3, 2, 1, 8, 1, 2, 1, 3, 1, 6, 1, 6, 2, 4, 1, 9, 1, 2, 2, 8, 1, 8, 1, 3, 1, 2, 1, 10, 1, 4, 1, 3, 1, 6, 2, 4, 2, 2, 1, 12, 1, 2, 3, 7, 1, 8, 1, 6, 2, 4, 1, 12, 1, 2, 2, 3, 1, 6, 1, 10, 2, 2, 1, 12, 1, 2, 1, 4, 1, 8, 1, 6, 1, 2, 1, 12, 1, 2, 2, 6, 1, 6, 1, 4, 4 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS Number of such positive integers k that both k and A000120(k) [the Hamming weight of k] divide n. LINKS Antti Karttunen, Table of n, a(n) for n = 1..65537 FORMULA a(n) = Sum_{d|n} [A000120(d) does divide n], where [ ] is the Iverson bracket. a(n) = A000005(n) - A324393(n). a(p) = 1 for all odd primes p. MATHEMATICA a[n_] := DivisorSum[n, 1 &, Divisible[n, DigitCount[#, 2, 1]] &]; Array[a, 100] (* Amiram Eldar, Dec 04 2020 *) PROG (PARI) A324392(n) = sumdiv(n, d, !(n%hammingweight(d))); CROSSREFS Cf. A000005, A000120, A324393. Cf. also A093653, A192895, A266342, A292257. Sequence in context: A328578 A094741 A285577 * A340273 A029234 A102613 Adjacent sequences:  A324389 A324390 A324391 * A324393 A324394 A324395 KEYWORD nonn,base AUTHOR Antti Karttunen, Mar 05 2019 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 January 20 19:03 EST 2022. Contains 350472 sequences. (Running on oeis4.)