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A062024 a(n) = ((n+1)^n + (n-1)^n)/2. 8
1, 1, 5, 36, 353, 4400, 66637, 1188544, 24405761, 567108864, 14712104501, 421504185344, 13218256749601, 450353989316608, 16565151205544957, 654244800082329600, 27614800115689879553, 1240529732459024678912, 59095217374989483261925, 2975557672677668838178816 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

COMMENTS

Let b(n) = A302583(n) = ((n+1)^n - (n-1)^n)/2 = 0, 1, 4, 28, 272, ... then lim_{n -> infinity} b(n)/a(n) = tanh(1) = 0.76159415... . - Thomas Ordowski, Dec 06 2012

Obviously, a(n) is always odd number for even n. - Altug Alkan, Sep 28 2015

LINKS

Harry J. Smith, Table of n, a(n) for n = 0..100

FORMULA

a(n) = n! * [x^n] exp(n*x)*cosh(x). - Ilya Gutkovskiy, Apr 10 2018

EXAMPLE

a(3) = (4^3 + 2^3)/2 = 36.

MAPLE

A062024:=n->((n+1)^n + (n-1)^n)/2; seq(A062024(n), n=0..20); # Wesley Ivan Hurt, Nov 13 2013

MATHEMATICA

a[n_]:=((n-1)^n+(n+1)^n)/2; a[Range[0, 20]] (* Vladimir Joseph Stephan Orlovsky, Feb 07 2010; modified by G. C. Greubel, Jan 03 2020 *)

Table[((n+1)^n + (n-1)^n)/2, {n, 0, 20}] (* Vincenzo Librandi, Sep 28 2015 *)

PROG

(PARI) { for (n=0, 100, write("b062024.txt", n, " ", ((n + 1)^n + (n - 1)^n)/2) ) } \\ Harry J. Smith, Jul 29 2009

(MAGMA) [((n+1)^n + (n-1)^n)/2: n in [0..20]]; // Vincenzo Librandi, Sep 28 2015

(Sage) [((n+1)^n + (n-1)^n)/2 for n in (0..20)] # G. C. Greubel, Jan 03 2020

(GAP) List([0..20], n-> ((n+1)^n + (n-1)^n)/2); # G. C. Greubel, Jan 03 2020

CROSSREFS

Cf. A302583.

Sequence in context: A099391 A008785 A081918 * A031971 A247496 A302584

Adjacent sequences:  A062021 A062022 A062023 * A062025 A062026 A062027

KEYWORD

nonn

AUTHOR

Amarnath Murthy, Jun 02 2001

EXTENSIONS

More terms from Larry Reeves (larryr(AT)acm.org) and Jason Earls, Jun 06 2001

Offset changed from 1 to 0 by Harry J. Smith, Jul 29 2009

a(18)-a(19) from Vincenzo Librandi, Sep 28 2015

STATUS

approved

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Last modified September 27 03:21 EDT 2020. Contains 337380 sequences. (Running on oeis4.)