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A084377 a(n) = n^3 + 7. 3
7, 8, 15, 34, 71, 132, 223, 350, 519, 736, 1007, 1338, 1735, 2204, 2751, 3382, 4103, 4920, 5839, 6866, 8007, 9268, 10655, 12174, 13831, 15632, 17583, 19690, 21959, 24396, 27007, 29798, 32775, 35944, 39311, 42882, 46663, 50660, 54879, 59326 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,1

COMMENTS

These numbers cannot be perfect squares. See Hilliard link for a proof. - Cino Hilliard, Sep 03 2006

LINKS

Vincenzo Librandi, Table of n, a(n) for n = 0..1000

Cino Hilliard, Proof that n^3+7 != k^2 for all integers n,k. [Broken link]

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

FORMULA

G.f.: (7 - 20*x + 25*x^2 - 6*x^3)/(1 - x)^4. - Vincenzo Librandi, Jun 10 2016

a(n) = 4*a(n-1) - 6*a(n-2) + 4*a(n-3) - a(n-4) for n>3. - Vincenzo Librandi, Jun 10 2016

MATHEMATICA

Table[n^3 + 7, {n, 0, 60}] (* Vladimir Joseph Stephan Orlovsky, Apr 15 2011 *)

PROG

(PARI) a(n) = n^3 + 7;

(MAGMA) [n^3+7: n in [0..50]]; // Vincenzo Librandi, Jun 10 2016

CROSSREFS

Cf. A000578, A084378, A084381.

Sequence in context: A020690 A191413 A066971 * A041675 A041098 A041427

Adjacent sequences:  A084374 A084375 A084376 * A084378 A084379 A084380

KEYWORD

easy,nonn

AUTHOR

Cino Hilliard, Jun 23 2003

EXTENSIONS

More terms from Franklin T. Adams-Watters, Aug 29 2006

STATUS

approved

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Last modified April 21 08:51 EDT 2019. Contains 322328 sequences. (Running on oeis4.)