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A083474 T(n)^2-n!, where T(n) is the n-th triangular number. 1
0, 7, 30, 76, 105, -279, -4256, -39024, -360855, -3625775, -39912444, -478995516, -6227012519, -87178280175, -1307674353600, -20922789869504, -355687428072591, -6402373705698759, -121645100408795900, -2432902008176595900, -51090942171709386639 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Vincenzo Librandi, Table of n, a(n) for n = 1..200

EXAMPLE

a(3)=T(3)^2-3!=6^2-6=36-6=30

MATHEMATICA

Table[((n(n+1))/2)^2-n!, {n, 30}] (* Harvey P. Dale, Nov 23 2011 *)

PROG

(PARI) t(n)=n*(n+1)/2 for(i=1, 50, print1(", "t(i)^2-i!))

CROSSREFS

Cf. A000142, A000217.

Sequence in context: A116283 A139274 A086640 * A030440 A256225 A232093

Adjacent sequences:  A083471 A083472 A083473 * A083475 A083476 A083477

KEYWORD

sign

AUTHOR

Jon Perry, Jun 08 2003

EXTENSIONS

Corrected by Harvey P. Dale, Nov 23 2011

STATUS

approved

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Last modified August 13 02:52 EDT 2020. Contains 336441 sequences. (Running on oeis4.)