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A168061 Denominator of (n+3) / ((n+2) * (n+1) * n). 2
3, 24, 10, 120, 105, 112, 252, 720, 165, 1320, 858, 728, 1365, 3360, 680, 4896, 2907, 2280, 3990, 9240, 1771, 12144, 6900, 5200, 8775, 19656, 3654, 24360, 13485, 9920, 16368, 35904, 6545, 42840, 23310, 16872, 27417, 59280, 10660, 68880, 37023, 26488, 42570 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Numerator of ((n+3)/(n+2)/(n+1)/n) = A060789(n).

LINKS

G. C. Greubel, Table of n, a(n) for n = 1..1000

Index entries for linear recurrences with constant coefficients, signature (0,0,0,0,0,4,0,0,0,0,0,-6,0,0,0,0,0,4,0,0,0,0,0,-1).

FORMULA

a(n) = 4*a(n-6) -6*a(n-12) +4*a(n-18) -a(n-24) = A007531(n+2)/A089145(n). - R. J. Mathar, Nov 18 2009

G.f.: x*(3 + 24*x + 10*x^2 + 120*x^3 + 105*x^4 + 112*x^5 + 240*x^6 + 624*x^7 + 125*x^8 + 840*x^9 + 438*x^10 + 280*x^11 + 375*x^12 + 624*x^13 + 80*x^14 + 336*x^15 + 105*x^16 + 40*x^17 + 30*x^18 + 24*x^19 + x^20) / ((1 - x)^4*(1 + x)^4*(1 - x + x^2)^4*(1 + x + x^2)^4). - Colin Barker, Feb 04 2018

MAPLE

seq(denom((n+3)/(n+2)/(n+1)/n), n=1..10^3); # Muniru A Asiru, Feb 04 2018

MATHEMATICA

Table[Denominator[(n+3)/(n+2)/(n+1)/n], {n, 60}]

LinearRecurrence[{0, 0, 0, 0, 0, 4, 0, 0, 0, 0, 0, -6, 0, 0, 0, 0, 0, 4, 0, 0, 0, 0, 0, -1}, {3, 24, 10, 120, 105, 112, 252, 720, 165, 1320, 858, 728, 1365, 3360, 680, 4896, 2907, 2280, 3990, 9240, 1771, 12144, 6900, 5200}, 50] (* Harvey P. Dale, Apr 06 2017 *)

PROG

(PARI) vector(50, n, denominator(((n+3)/(n+2)/(n+1)/n))) \\ Colin Barker, Feb 04 2018

(PARI) Vec(x*(3 + 24*x + 10*x^2 + 120*x^3 + 105*x^4 + 112*x^5 + 240*x^6 + 624*x^7 + 125*x^8 + 840*x^9 + 438*x^10 + 280*x^11 + 375*x^12 + 624*x^13 + 80*x^14 + 336*x^15 + 105*x^16 + 40*x^17 + 30*x^18 + 24*x^19 + x^20) / ((1 - x)^4*(1 + x)^4*(1 - x + x^2)^4*(1 + x + x^2)^4) + O(x^60)) \\ Colin Barker, Feb 04 2018

(GAP) List([1..10^3], n->DenominatorRat((n+3)/(n+2)/(n+1)/n)); # Muniru A Asiru, Feb 04 2018

CROSSREFS

Cf. A060789.

Sequence in context: A062834 A047980 A084702 * A261381 A065430 A175471

Adjacent sequences:  A168058 A168059 A168060 * A168062 A168063 A168064

KEYWORD

nonn,easy

AUTHOR

Vladimir Joseph Stephan Orlovsky, Nov 17 2009

STATUS

approved

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Last modified December 4 21:30 EST 2020. Contains 338939 sequences. (Running on oeis4.)