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!)
 A229337 Sum of products of elements of nonempty subsets of divisors of n. 3
 1, 5, 7, 29, 11, 167, 15, 269, 79, 395, 23, 10919, 27, 719, 767, 4589, 35, 31919, 39, 41579, 1407, 1655, 47, 2456999, 311, 2267, 2239, 104399, 59, 5499647, 63, 151469, 3263, 3779, 3455, 76767599, 75, 4679, 4479, 15343019, 83, 19071359, 87, 372599, 353279, 6767 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS Number of nonempty subsets of divisors of n = A100587(n). LINKS FORMULA Let a, b, c, ..., k be all divisors of n; a(n) = (a+1) * (b+1) * ... * (k+1) - 1. a(p) = 2p+1, a(p^2) = 2(p+1)(p^2+1) - 1. a(n) = A020696(n) - 1. EXAMPLE For n = 2^2 = 4; divisors of 4: {1, 2, 4}; nonempty subsets of divisors of n: {1}, {2}, {4}, {1, 2}, {1, 4}, {2, 4}, {1, 2, 4}; sum of products of elements of subsets = 1 + 2 + 4 + 2 + 4 + 8 + 8 = 29 = (1+1) * (2+1) * (4+1) - 1. CROSSREFS Cf. A229335 (sum of sums of elements of nonempty subsets of divisors of n), A229336 (product of sums of elements of nonempty subsets of divisors of n), A229338 (product of products of elements of nonempty subsets of divisors of n). Sequence in context: A185302 A179305 A307100 * A227857 A266078 A147993 Adjacent sequences:  A229334 A229335 A229336 * A229338 A229339 A229340 KEYWORD nonn AUTHOR Jaroslav Krizek, Sep 20 2013 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 6 08:44 EDT 2020. Contains 333268 sequences. (Running on oeis4.)