A277875 a(n) is the odd multiplier q in the expressions 2*(q*2^n - 1) and 2*(q*3^n - 1) of numbers A277215(n) and A277874(n), respectively.

1, 7, 1, 1, 1, 19, 13, 1, 1, 1, 1, 7, 5, 11, 1, 1, 1, 7, 11, 1, 1, 1, 1, 1, 1, 7, 5, 1, 1, 7, 1, 1, 1, 1, 1, 11, 5, 1, 1, 1, 1, 1, 1, 1, 1, 7, 5, 1, 1, 7, 1, 1, 1, 7, 1, 1, 1, 7, 5, 11, 1, 7, 5, 1, 1, 7, 1, 1, 1, 11, 1, 1, 1, 1, 1, 11, 1, 7, 1, 1, 1, 1, 1, 11, 1, 1, 1, 1, 1, 1, 1, 1, 1, 7, 1, 1, 1, 1, 1, 1

Offset: 0

Author

Hartmut F. W. Hoft, Nov 03 2016

Keywords

• nonn

Comments

The position numbers for odd numbers 5, 7, 11, 13 and 19 for the first 200 numbers in the sequence are listed in the Comments section of A277215.

Examples

			a(0) = 1 since 0 = 2*(1*2^0 - 1) is the start and end of the first alternating sequence of 1 element and the maximum of its trajectory.
a(5) = 19 since 9232 = 2*(19*3^5 - 1) is the last element in the first alternating sequence of 11 elements - 1214, 607, 1822, 911, 2734, 1367, 4102, 2051, 6154, 3077, 9232 - that ends in the trajectory maximum.
		

Crossrefs

Cf. A277215, A277874.

Programs

Mathematica

(* we use function altdata[] from A277215 *)
a277875[n_]:=Map[#[[2]]&, altdata[2,n]]
Join[{1,7}, a277875[99]] (* sequence data *)