|
|
A032797
|
|
Numbers n such that n(n+1)(n+2)...(n+10) /(n+(n+1)+(n+2)+...+(n+10)) is a multiple of n.
|
|
0
|
|
|
1, 2, 3, 4, 5, 7, 8, 9, 10, 12, 13, 14, 15, 16, 18, 19, 20, 21, 23, 24, 25, 26, 27, 29, 30, 31, 32, 34, 35, 36, 37, 38, 40, 41, 42, 43, 45, 46, 47, 48, 49, 51, 52, 53, 54, 56, 57, 58, 59, 60, 62, 63, 64, 65, 67, 68, 69, 70, 71, 73, 74, 75, 76, 78, 79, 80, 81, 82, 84, 85, 86
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
1,2
|
|
COMMENTS
|
Equals natural numbers minus '6,11,17,22,28,...' (= previous term +5,+6,+5,+6,...).
|
|
LINKS
|
Index entries for linear recurrences with constant coefficients, signature (1, 0, 0, 0, 0, 0, 0, 0, 1, -1).
|
|
FORMULA
|
a(n) = a(n-1) + a(n-9) - a(n-10) for n > 10.
G.f.: x*(x^9 + x^8 + x^7 + x^6 + 2*x^5 + x^4 + x^3 + x^2 + x + 1)/(x^10 - x^9 - x + 1). (End)
|
|
MATHEMATICA
|
nmnQ[n_]:=With[{c=n+Range[0, 10]}, Divisible[Times@@c/Total[c], n]]; Select[ Range[ 100], nmnQ] (* or *) LinearRecurrence[{1, 0, 0, 0, 0, 0, 0, 0, 1, -1}, {1, 2, 3, 4, 5, 7, 8, 9, 10, 12}, 80] (* Harvey P. Dale, May 07 2017 *)
|
|
PROG
|
|
|
CROSSREFS
|
|
|
KEYWORD
|
nonn,easy
|
|
AUTHOR
|
|
|
EXTENSIONS
|
Typo in definition corrected by Zak Seidov, Aug 06 2016
|
|
STATUS
|
approved
|
|
|
|