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A070261 4th diagonal of triangle defined in A051537. 2
4, 10, 2, 28, 40, 6, 70, 88, 12, 130, 154, 20, 208, 238, 30, 304, 340, 42, 418, 460, 56, 550, 598, 72, 700, 754, 90, 868, 928, 110, 1054, 1120, 132, 1258, 1330, 156, 1480, 1558, 182, 1720, 1804, 210, 1978, 2068, 240, 2254, 2350, 272, 2548, 2650, 306, 2860 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Colin Barker, Table of n, a(n) for n = 1..1000

Index entries for linear recurrences with constant coefficients, signature (0,0,3,0,0,-3,0,0,1).

FORMULA

a(n) = lcm(n + 3, n) / gcd(n + 3, n).

From Colin Barker, Mar 27 2017: (Start)

G.f.: 2*x*(2 + 5*x + x^2 + 8*x^3 + 5*x^4 - x^6 - x^7) / ((1 - x)^3*(1 + x + x^2)^3).

a(n) = 3*a(n-3) - 3*a(n-6) + a(n-9) for n>9.

(End)

MATHEMATICA

Table[ LCM[i + 3, i] / GCD[i + 3, i], {i, 1, 60}]

PROG

(PARI) Vec(2*x*(2 + 5*x + x^2 + 8*x^3 + 5*x^4 - x^6 - x^7) / ((1 - x)^3*(1 + x + x^2)^3) + O(x^60)) \\ Colin Barker, Mar 27 2017

CROSSREFS

Sequence in context: A087212 A048870 A244152 * A054048 A121512 A291527

Adjacent sequences:  A070258 A070259 A070260 * A070262 A070263 A070264

KEYWORD

nonn,easy

AUTHOR

Amarnath Murthy, May 09 2002

EXTENSIONS

Edited by Robert G. Wilson v, May 10 2002

STATUS

approved

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Last modified October 17 01:03 EDT 2019. Contains 328103 sequences. (Running on oeis4.)