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A000472 a(n) = a(n-1)^2 + (a(n-2) + 1)(a(n-1) - a(n-2)^2 ). 1
2, 5, 28, 802, 643726, 414383582242, 171713753231982206218246, 29485613049014079571725771288849499850026859242 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

REFERENCES

Damiani, E.; D'Antona, O.; Naldi, G.; and Pavarino, L.; Tiling bricks with bricks. Stud. Appl. Math. 83 (1990), number 2, 91-110.

LINKS

Vincenzo Librandi, Table of n, a(n) for n = 1..14

Index entries for sequences related to bricks

MAPLE

A000472 := proc(n) option remember; if n<=2 then 3*n-1 else A000472(n-1)^2+(1+A000472(n-2))*(A000472(n-1)-A000472(n-2)^2); fi; end;

MATHEMATICA

RecurrenceTable[{a[1]==2, a[2]==5, a[n]==a[n-1]^2+(a[n-2]+1)(a[n-1]- a[n-2]^2)}, a[n], {n, 10}] (* Harvey P. Dale, Sep 29 2011 *)

PROG

(MAGMA) I:=[2, 5]; [n le 2 select I[n] else  Self(n-1)^2 + (Self(n-2)+1)*(Self(n-1)-Self(n-2)^2 ): n in [1..10]]; // Vincenzo Librandi, Sep 30 2011

(Haskell)

a000472 n = a000472_list !! (n-1)

a000472_list = 2 : 5 : zipWith (+) (map (^ 2) $ tail a000472_list)

   (zipWith (*) (map (+ 1) a000472_list)

                (zipWith (-) (tail a000472_list)

                             (map (^ 2) a000472_list)))

-- Reinhard Zumkeller, Oct 03 2012

CROSSREFS

Sequence in context: A068069 A105787 A110497 * A248235 A049050 A178322

Adjacent sequences:  A000469 A000470 A000471 * A000473 A000474 A000475

KEYWORD

nonn,nice,easy

AUTHOR

Ottavio D'Antona [ dantona(AT)hermes.dsi.unimi.it ]

STATUS

approved

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Last modified August 21 00:45 EDT 2017. Contains 290855 sequences.