

A144396


The odd numbers greater than 1.


18



3, 5, 7, 9, 11, 13, 15, 17, 19, 21, 23, 25, 27, 29, 31, 33, 35, 37, 39, 41, 43, 45, 47, 49, 51, 53, 55, 57, 59, 61, 63, 65, 67, 69, 71, 73, 75, 77, 79, 81, 83, 85, 87, 89, 91, 93, 95, 97, 99, 101, 103, 105, 107, 109, 111, 113, 115, 117, 119, 121, 123, 125, 127, 129, 131, 133
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OFFSET

1,1


COMMENTS

Last number of the nth row of the triangle described in A142717.
If negated, these are also the values at local minima of the sequence A141620.
a(n) is the shortest leg of the nth Pythagorean triple with consecutive longer leg and hypotenuse. The nth such triple is given by (2n+1,2n^2+2n, 2n^2+2n+1), so that the longer legs are A046092(n) and the hypotenuses are A099776(n).  Ant King, Feb 10 2011
Numbers k such that the symmetric representation of sigma(k) has a pair of bars as its ends (cf. A237593).  Omar E. Pol, Sep 28 2018


LINKS

Muniru A Asiru, Table of n, a(n) for n = 1..1000
Index entries for linear recurrences with constant coefficients, signature (2,1)


FORMULA

a(n) = A005408(n+1) = A000290(n+1)  A000290(n).
G.f.: x*(3x)/(1x)^2.  Jaume Oliver Lafont, Aug 30 2009
a(n) = A254858(n1,2).  Reinhard Zumkeller, Feb 09 2015


MAPLE

seq(n, n=3..200, 2); # Muniru A Asiru, Sep 28 2018


MATHEMATICA

Range[3, 200, 2] (* Vladimir Joseph Stephan Orlovsky, Feb 19 2012 *)


PROG

(Haskell)
a144396 = (+ 1) . (* 2)
a144396_list = [3, 5 ..]  Reinhard Zumkeller, Feb 09 2015
(GAP) List([3, 5..200], n>n); # Muniru A Asiru, Sep 28 2018


CROSSREFS

Complement of A004275 and of A004277.
Cf. A000217, A002378, A005408, A007395, A046092, A099776, A237593, A254858.
Sequence in context: A004273 A005408 A176271 * A060747 A089684 A283002
Adjacent sequences: A144393 A144394 A144395 * A144397 A144398 A144399


KEYWORD

nonn,less,easy


AUTHOR

Paul Curtz, Oct 03 2008


EXTENSIONS

Edited by R. J. Mathar, May 21 2009


STATUS

approved



