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!)
 A280685 a(n) = sum of the divisors of the product of the divisors of n. 1
 1, 3, 4, 15, 6, 91, 8, 127, 40, 217, 12, 5080, 14, 399, 403, 2047, 18, 16395, 20, 19812, 741, 931, 24, 991111, 156, 1281, 1093, 50800, 30, 2929531, 32, 65535, 1729, 2149, 1767, 30203052, 38, 2667, 2379, 6397171, 42, 10506551, 44, 185928, 170508, 3871, 48 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 LINKS FORMULA a(n) = A000203(A007955(n)). a(p) = p + 1  for p = primes (A000040). a(A000079(n)) = 2* A007955(n)) - 1. EXAMPLE For n = 4; a(n) = sigma (1*2*4) = sigma(8) = 15. PROG (MAGMA) [&+[d: d in Divisors(&*[d: d in Divisors(n)])]: n in [1..100]] CROSSREFS Cf. A000079, A000040, A000203, A007955, A280582, A280684. Sequence in context: A071167 A194924 A205489 * A076365 A070971 A130113 Adjacent sequences:  A280682 A280683 A280684 * A280686 A280687 A280688 KEYWORD nonn AUTHOR Jaroslav Krizek, Jan 07 2017 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 1 20:54 EDT 2020. Contains 333168 sequences. (Running on oeis4.)