A019328 - OEIS

%I #18 Feb 26 2024 09:59:31

%S 9,11,111,101,11111,91,1111111,10001,1001001,9091,11111111111,9901,

%T 1111111111111,909091,90090991,100000001,11111111111111111,999001,

%U 1111111111111111111,99009901,900900990991,9090909091,11111111111111111111111,99990001

%N Cyclotomic polynomials at x=10.

%C See A138940 for indices n for which a(n) is prime. - _M. F. Hasler_, Jan 09 2015

%H Paolo Xausa, <a href="/A019328/b019328.txt">Table of n, a(n) for n = 1..900</a>

%H <a href="/index/Cy#CyclotomicPolynomialsValuesAtX">Index entries for cyclotomic polynomials, values at X</a>

%p with(numtheory,cyclotomic); f := n->subs(x=10,cyclotomic(n,x)); seq(f(i),i=0..64);

%t Cyclotomic[Range[30], 10] (* _Paolo Xausa_, Feb 26 2024 *)

%o (PARI) A019328(n)=polcyclo(n,10) \\ Simplified by _M. F. Hasler_, Jan 09 2015

%K nonn

%O 1,1

%A _Simon Plouffe_