A130917 a(n) is the sum of the digital roots of all of the previous terms.

1, 1, 2, 4, 8, 16, 23, 28, 29, 31, 35, 43, 50, 55, 56, 58, 62, 70, 77, 82, 83, 85, 89, 97, 104, 109, 110, 112, 116, 124, 131, 136, 137, 139, 143, 151, 158, 163, 164, 166, 170, 178, 185, 190, 191, 193, 197, 205

Offset: 1

Author

Stephen Casey (hexomino(AT)gmail.com), Aug 23 2007

Keywords

• easy
• nonn
• base

Comments

Essentially identical to A007612, which is the main entry for this sequence. - N. J. A. Sloane, Aug 25 2007

Examples

			a(8) = 28 because the digital roots of the previous terms are 1,1,2,4,8,7 and 5 and 1+1+2+4+8+7+5 = 28
		

Links

• Index entries for linear recurrences with constant coefficients, signature (2,-1,-1,2,-1).

Crossrefs

Cf. A007612.

Programs

PARI

Vec(x*(5*x^5+x^4+2*x^3+x^2-x+1)/((x-1)^2*(x+1)*(x^2-x+1)) + O(x^100)) \\ Colin Barker, Jan 17 2014

Formula

G.f.: x*(5*x^5+x^4+2*x^3+x^2-x+1) / ((x-1)^2*(x+1)*(x^2-x+1)). - Colin Barker, Jan 17 2014