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A166931 Numbers n with property that n mod k is k-1 for all k = 2..9. 1

%I

%S 2519,5039,7559,10079,12599,15119,17639,20159,22679,25199,27719,30239,

%T 32759,35279,37799,40319,42839,45359,47879,50399,52919,55439,57959,

%U 60479,62999,65519,68039,70559,73079,75599,78119,80639,83159,85679

%N Numbers n with property that n mod k is k-1 for all k = 2..9.

%H G. C. Greubel, <a href="/A166931/b166931.txt">Table of n, a(n) for n = 1..1000</a>

%H <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (2, -1).

%F a(n) = 2519 + n*2520.

%F From _G. C. Greubel_, May 28 2016: (Start)

%F a(n) = 2*a(n-1) - a(n-2).

%F G.f.: (2519 + x)/(1-x)^2.

%F E.g.f.: (2519 + 2520*x)*exp(x). (End)

%p isA166931 := proc(n) for k from 2 to 9 do if n mod k <> k-1 then return false; end if; end do; true; end proc: for n from 1 to 500000 do if isA166931(n) then printf("%d,",n) ; end if; end do ; # _R. J. Mathar_, Nov 02 2009

%t Select[Range[90000],And@@Table[Mod[#,k]==k-1,{k,2,9}]&] (* _Harvey P. Dale_, Jun 14 2011 *)

%t LinearRecurrence[{2, -1}, {2519, 5039}, 50] (* _G. C. Greubel_, May 28 2016 *)

%K nonn,easy

%O 1,1

%A _Luc Comeau-Montasse_, Oct 23 2009

%E Edited by _N. J. A. Sloane_, Oct 25 2009

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Last modified August 14 06:25 EDT 2020. Contains 336477 sequences. (Running on oeis4.)