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

0, 11, 22, 27, 44, 50, 66, 84, 104, 126, 150, 176, 204, 234, 266, 300, 336, 374, 414, 456, 500, 546, 594, 644, 696, 750, 806, 864, 924, 986, 1050, 1116, 1184, 1254, 1326, 1400, 1476, 1554, 1634, 1716, 1800, 1886, 1974, 2064, 2156, 2250, 2346, 2444, 2544, 2646

Offset

0,2

Links

Colin Barker, Table of n, a(n) for n = 0..1000

Index entries for linear recurrences with constant coefficients, signature (3,-3,1).

Formula

From Colin Barker, Nov 24 2014: (Start)

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

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

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)

E.g.f.: (x/2)*(10 + 8*x + x^2 + 2*(x + 6)*exp(x)). - G. C. Greubel, Aug 28 2017

Maple

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

Mathematica

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

Prog

(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

Crossrefs

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

Cf. A028557 for n > 4. - R. J. Mathar, Aug 09 2009

Sequence in context: A234314 A258738 A160272 * A366093 A178736 A054728

Adjacent sequences: A164003 A164004 A164005 * A164007 A164008 A164009

Keyword

nonn,easy

Author

Omar E. Pol, Aug 08 2009

Extensions

Extended beyond a(12) by R. J. Mathar, Aug 09 2009

Status

approved