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A164006 Zero together with row 6 of the array in A163280. 5

%I

%S 0,11,22,27,44,50,66,84,104,126,150,176,204,234,266,300,336,374,414,

%T 456,500,546,594,644,696,750,806,864,924,986,1050,1116,1184,1254,1326,

%U 1400,1476,1554,1634,1716,1800,1886,1974,2064,2156,2250,2346,2444,2544,2646

%N Zero together with row 6 of the array in A163280.

%H Colin Barker, <a href="/A164006/b164006.txt">Table of n, a(n) for n = 0..1000</a>

%H <a href="/index/Rec#order_03">Index entries for linear recurrences with constant coefficients</a>, signature (3,-3,1).

%F From _Colin Barker_, Nov 24 2014: (Start)

%F a(n) = n*(n+5) for n > 4.

%F a(n) = 3*a(n-1) - 3*a(n-2) + a(n-3) for n > 7.

%F G.f.: x*(8*x^6 - 21*x^5 + 23*x^4 - 18*x^3 + 6*x^2 + 11*x - 11) / (x-1)^3. (End)

%F E.g.f.: (x/2)*(10 + 8*x + x^2 + 2*(x + 6)*exp(x)). - _G. C. Greubel_, Aug 28 2017

%p A033676 := proc(n) local a,d; a := 0 ; for d in numtheory[divisors](n) do if d^2 <= n then a := max(a,d) ; fi; od: a; end: A163280 := proc(n,k) local r,T ; r := 0 ; for T from k^2 by k do if A033676(T) = k then r := r+1 ; if r = n then RETURN(T) ; fi; fi; od: end: A164006 := proc(n) if n = 0 then 0; else A163280(6,n) ; fi; end: seq(A164006(n),n=0..80) ; # _R. J. Mathar_, Aug 09 2009

%t Join[{0,11,22,27}, Table[n*(n + 5), {n, 4, 50}]] (* _G. C. Greubel_, Aug 28 2017 *)

%o (PARI) concat(0, Vec(x*(8*x^6-21*x^5+23*x^4-18*x^3+6*x^2+11*x-11)/(x-1)^3 + O(x^100))) \\ _Colin Barker_, Nov 24 2014

%Y Cf. A008578, A161344, A161345, A163280, A164000, A164005, A164007.

%Y Cf. A028557 for n > 4. - _R. J. Mathar_, Aug 09 2009

%K nonn,easy

%O 0,2

%A _Omar E. Pol_, Aug 08 2009

%E Extended beyond a(12) by _R. J. Mathar_, Aug 09 2009

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Last modified November 18 17:45 EST 2019. Contains 329287 sequences. (Running on oeis4.)