The OEIS mourns the passing of Jim Simons and is grateful to the Simons Foundation for its support of research in many branches of science, including the OEIS.
login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A283550 Numbers that are not the sum of abundant numbers (not necessarily distinct). 4
1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 13, 14, 15, 16, 17, 19, 21, 22, 23, 25, 26, 27, 28, 29, 31, 33, 34, 35, 37, 39, 41, 43, 45, 46, 47, 49, 51, 53, 55, 57, 59, 61, 63, 65, 67, 69, 71, 73, 75, 77, 79, 81, 83, 85, 87, 89, 91, 93, 95, 97, 99, 101, 103, 105, 107 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,2
COMMENTS
a(496) = 991 is the last term.
Subsequence of A048242 (Numbers that are not the sum of two abundant numbers).
Giovanni Resta noticed that 991 is the largest number that is not a sum of abundant numbers.
LINKS
Giovanni Resta, abundant numbers
EXAMPLE
20161 = 12 + 304 + 19845 is the sum of 3 abundant numbers and thus not in the sequence (although it is in A048242, since it is not the sum of 2 abundant numbers).
MATHEMATICA
AbundantQ[n_] := DivisorSigma[1, n] > 2 n; a = Select[Range[1000], AbundantQ[#] &]; nn = Dimensions[a][[1]]; t = Rest[CoefficientList[ Series[Product[(1 + x^a[[k]]), {k, nn}], {x, 0, a[[-1]]}], x]]; f = Flatten[Position[t, 0]]
CROSSREFS
Sequence in context: A360553 A067340 A263837 * A271113 A325369 A317101
KEYWORD
nonn,fini,full
AUTHOR
Amiram Eldar, Mar 10 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 | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified June 18 11:09 EDT 2024. Contains 373481 sequences. (Running on oeis4.)