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!)
A228961 Smallest sets of 4 consecutive abundant numbers in arithmetic progression. The initial abundant number is listed. 6
114, 120, 228, 234, 240, 282, 348, 420, 582, 588, 654, 660, 708, 840, 1002, 1008, 1014, 1068, 1122, 1242, 1248, 1254, 1260, 1380, 1434, 1542, 1548, 1674, 1794, 1800, 1908, 1914, 1998, 2094, 2100, 2208, 2214, 2220, 2262, 2268, 2328, 2334, 2340, 2502, 2508 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
LINKS
EXAMPLE
114, 120, 126, 132 is the smallest set of 4 consecutive abundant numbers in arithmetic progression so 114 is in the list.
MATHEMATICA
AbundantQ[n_] := DivisorSigma[1, n] > 2 n; m = 2; z1 = 18; cd = 6; a = {}; Do[If[AbundantQ[n], If[n - z1 == cd, m = m + 1; If[m > 3, AppendTo[a, n - 3*cd]], m = 2; cd = n - z1]; z1 = n], {n, 19, 1000000}]; a
CROSSREFS
Sequence in context: A138693 A272303 A260213 * A057440 A113537 A352233
KEYWORD
nonn
AUTHOR
Shyam Sunder Gupta, Nov 10 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 | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified March 4 16:59 EST 2024. Contains 370532 sequences. (Running on oeis4.)