A366822 a(n) is phi(n^n + 1) where phi is the Euler totient function.
1, 1, 4, 12, 256, 1040, 41472, 407680, 16515072, 152845056, 9897840000, 89493288192, 8732596764672, 129785922489600, 10576701872701440, 210729768933600000, 18446676793287966720, 275746753962112254720, 28084363369373740400640, 791359800910482004224000
Offset: 0
Keywords
Links
- Robert G. Wilson v, Table of n, a(n) for n = 0..72
- Eric Weisstein's World of Mathematics, Sierpinski Number of the First Kind
Programs
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Mathematica
{1}~Join~Array[EulerPhi[#^# + 1] &, 19] (* Michael De Vlieger, Oct 24 2023 *) -
PARI
a(n) = eulerphi(n^n+1);