A156760 5*4^n-1.

4, 19, 79, 319, 1279, 5119, 20479, 81919, 327679, 1310719, 5242879, 20971519, 83886079, 335544319, 1342177279, 5368709119, 21474836479, 85899345919, 343597383679, 1374389534719, 5497558138879, 21990232555519, 87960930222079, 351843720888319

Offset: 0

Author

Paul Curtz, Feb 15 2009

Keywords

• nonn
• easy

Comments

Second column of the array A132207, or, if this array is flattened, a(n)=A132207(A007583(n)).

Examples

			Binary.......................................Decimal
100................................................4
10011.............................................19
1001111...........................................79
100111111........................................319
10011111111.....................................1279
1001111111111...................................5119
100111111111111................................20479
10011111111111111..............................81919
1001111111111111111...........................327679
100111111111111111111........................1310719
10011111111111111111111......................5242879
1001111111111111111111111...................20971519
100111111111111111111111111.................83886079
10011111111111111111111111111..............335544319
1001111111111111111111111111111...........1342177279
... - _Philippe Deléham_, Feb 23 2014
		

Links

• Vincenzo Librandi, Table of n, a(n) for n = 0..500

Programs

Magma

[5*4^n-1: n in [0..30]]; // Vincenzo Librandi, Jul 02 2011

Mathematica

Table[5*4^n - 1, {n, 0, 18}] (* Michael De Vlieger, Apr 20 2015 *)

Formula

a(n) mod 9 = A070403(n+2).

a(n+1) = 10*A083420(n)+9 .

a(n) = 5*A000302(n)-1.

a(n) = ( A024036(n+1)+A140529(n) )/2.

a(n) = 4a(n-1)+3, a(0)=4.

a(n) = A003947(n+1)-1 = 5*a(n-1)-4*a(n-2). G.f.: (4-x)/((1-x)(1-4x)). - R. J. Mathar, Feb 23 2009

a(n) = A198693(n) + 2^(2n+1). - Bob Selcoe, Apr 20 2015

Extensions

Edited and extended by R. J. Mathar, Feb 23 2009