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A143855 Ulam's spiral (ESE spoke). 2
1, 10, 51, 124, 229, 366, 535, 736, 969, 1234, 1531, 1860, 2221, 2614, 3039, 3496, 3985, 4506, 5059, 5644, 6261, 6910, 7591, 8304, 9049, 9826, 10635, 11476, 12349, 13254, 14191, 15160, 16161, 17194, 18259, 19356, 20485, 21646, 22839, 24064 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Also sequence found by reading the segment (1, 10) together with the line from 10, in the direction 10, 51, ..., in the square spiral whose vertices are the generalized decagonal numbers A074377. - Omar E. Pol, Nov 05 2012

LINKS

Table of n, a(n) for n=1..40.

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

FORMULA

a(n) = 16n^2-39n+24. - R. J. Mathar, Sep 08 2008

G.f.: x*(1+7*x+24*x^2)/(1-x)^3. - Colin Barker, Aug 03 2012

MATHEMATICA

f[n_] := 16n^2 -39n +24; Array[f, 40] (* Vladimir Joseph Stephan Orlovsky, Sep 04 2008 *)

CoefficientList[Series[(1 + 7 x + 24 x^2) / (1 - x)^3, {x, 0, 40}], x] (* Vincenzo Librandi, Nov 08 2014 *)

PROG

(MAGMA) [16*n^2-39*n+24: n in [1..50]]; // Vincenzo Librandi, Nov 08 2014

(PARI) vector(50, n, 16*n^2-39*n+24) \\ Michel Marcus, Nov 08 2014

CROSSREFS

Sequence in context: A143558 A106041 A264044 * A124162 A077044 A069038

Adjacent sequences:  A143852 A143853 A143854 * A143856 A143857 A143858

KEYWORD

nonn,easy

AUTHOR

Vladimir Joseph Stephan Orlovsky, Sep 03 2008, Sep 04 2008

STATUS

approved

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Last modified August 17 11:14 EDT 2019. Contains 326057 sequences. (Running on oeis4.)