OFFSET
1,1
COMMENTS
Multiples of 4 with the unit digit equal to 4.
Positive integers that are the product of two integers ending with 2 (see A017293). - Stefano Spezia, Jul 25 2021
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 1..2000
Index entries for linear recurrences with constant coefficients, signature (2,-1).
FORMULA
a(n) = a(n-1) + 20.
a(n) = 4*A016861(n-1). - Wesley Ivan Hurt, Jan 17 2014
From Stefano Spezia, Jul 25 2021: (Start)
O.g.f.: 4*x*(1 + 4*x)/(1 - x)^2.
E.g.f.: 16 + 4*exp(x)*(5*x - 4).
a(n) = 2*a(n-1) - a(n-2) for n > 2. (End)
MAPLE
MATHEMATICA
Range[4, 1500, 20] (* Vladimir Joseph Stephan Orlovsky, Jun 01 2011 *)
PROG
(Magma) [20*n-16: n in [1..60]]; // Vincenzo Librandi, Jun 19 2011
(PARI) a(n)=20*n-16 \\ Charles R Greathouse IV, Aug 25 2014
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Odimar Fabeny, Jun 06 2008
EXTENSIONS
More terms from Reinhard Zumkeller, Jun 22 2008
STATUS
approved