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Search: id:A004664
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A004664 n! + n^2. +0
3
1, 2, 6, 15, 40, 145, 756, 5089, 40384, 362961, 3628900, 39916921, 479001744, 6227020969, 87178291396, 1307674368225, 20922789888256, 355687428096289, 6402373705728324, 121645100408832361, 2432902008176640400 (list; graph; listen)
OFFSET

0,2

COMMENT

It appears (conjectured by me) that n! + n^2 != m^2 for n>=1, m>=0 (n=0 is not included in above conjecture because obviously A004664(0) =1) I checked using PARI that indeed n! +n^2 doesn't yield perfect square for n>=1 up to n=30,000 [From Alexander R.Povolotsky (pevnev(AT)juno.com), Sep 26 2008]

LINKS

Index entries for sequences related to factorial numbers

MATHEMATICA

Table[n! + n^2, {n, 0, 20}] - Stefan Steinerberger (stefan.steinerberger(AT)gmail.com), Apr 11 2006

CROSSREFS

Sequence in context: A001654 A062106 A061322 this_sequence A074446 A121328 A139379

Adjacent sequences: A004661 A004662 A004663 this_sequence A004665 A004666 A004667

KEYWORD

nonn

AUTHOR

N. J. A. Sloane (njas(AT)research.att.com).

EXTENSIONS

One more term from Stefan Steinerberger (stefan.steinerberger(AT)gmail.com), Apr 11 2006

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Last modified November 25 20:09 EST 2009. Contains 167514 sequences.


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