A229903 a(n) = (190/99)*(100^A001651(n)-1).

190, 19190, 191919190, 19191919190, 191919191919190, 19191919191919190, 191919191919191919190, 19191919191919191919190, 191919191919191919191919190, 19191919191919191919191919190, 191919191919191919191919191919190

Offset: 1

Author

Jahangeer Kholdi, Oct 17 2013

Keywords

• nonn
• easy

Comments

This sequence is a subsequence of A097647. Because if 3 does not divide m then gcd(100^m-1,19*91)=1 and we have phi(190*(100^m-1)/99)=phi(190)*phi((100^m-1)/9)=phi(91)*phi((100^m-1)/99)=phi(91*(100^m-1)/99)=phi(reversal(190*(100^m-1)/99)).

Links

• Index entries for linear recurrences with constant coefficients, signature (1,1000000,-1000000).

Crossrefs

Cf. A000010, A001651, A004086, A097647.

Programs

Mathematica

Table[190/99*(100^Floor[(3n-1)/2]-1),{n,11}]

PARI

Vec(190*x*(10000*x^2+100*x+1)/((x-1)*(1000*x-1)*(1000*x+1)) + O(x^100)) \\ Colin Barker, Nov 01 2013

Formula

a(n) = (100/99)*(100^floor((3n-1)/2)-1).

G.f.: 190*x*(10000*x^2+100*x+1) / ((x-1)*(1000*x-1)*(1000*x+1)). - Colin Barker, Nov 01 2013