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URL: https://oeis.org/A180232

⇱ A180232 - OEIS

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A180232
a(n) = n*(17*n - 13)/2.
3
0, 2, 21, 57, 110, 180, 267, 371, 492, 630, 785, 957, 1146, 1352, 1575, 1815, 2072, 2346, 2637, 2945, 3270, 3612, 3971, 4347, 4740, 5150, 5577, 6021, 6482, 6960, 7455, 7967, 8496, 9042, 9605, 10185, 10782, 11396, 12027, 12675, 13340, 14022, 14721, 15437, 16170
OFFSET
0,2
FORMULA
a(n) = n + A051871(n).
a(n) = 3*a(n-1) - 3*a(n-2) + a(n-3).
G.f.: x*(2+15*x)/(1-x)^3. - R. J. Mathar, Aug 29 2010
E.g.f.: x *(4 + 17*x)*exp(x)/2. - G. C. Greubel, Aug 30 2019
MAPLE
seq(n*(17*n-13)/2, n=0..40); # G. C. Greubel, Aug 30 2019
MATHEMATICA
Table[(n(17n-13))/2, {n, 0, 50}] (* or *) LinearRecurrence[{3, -3, 1}, {0, 2, 21}, 50] (* Harvey P. Dale, Sep 14 2011 *)
PROG
(PARI) a(n)=1/2*(17*n^2 - 13*n);
(Magma) [n*(17*n-13)/2:n in [0..40]]; // Vincenzo Librandi, Sep 15 2011
(SageMath) [n*(17*n-13)/2 for n in (0..40)] # G. C. Greubel, Aug 30 2019
(GAP) List([0..40], n-> n*(17*n-13)/2); # G. C. Greubel, Aug 30 2019
CROSSREFS
Cf. A051871.
Cf. A226488. [Bruno Berselli, Jun 10 2013]
Sequence in context: A231807 A351118 A097718 * A075681 A212257 A034520
KEYWORD
nonn,easy
AUTHOR
Graziano Aglietti (mg5055(AT)mclink.it), Aug 18 2010
EXTENSIONS
More terms from R. J. Mathar, Aug 29 2010
STATUS
approved