The OEIS mourns the passing of Jim Simons and is grateful to the Simons Foundation for its support of research in many branches of science, including the OEIS.
login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A369291 Array read by antidiagonals: T(n,k) = phi(k^n-1)/n, where phi is Euler's totient function (A000010), n >= 1, k >= 2. 13

%I #8 Jan 28 2024 23:26:58

%S 1,1,1,2,2,2,2,4,4,2,4,4,12,8,6,2,12,20,32,22,6,6,8,56,48,120,48,18,4,

%T 18,36,216,280,288,156,16,6,16,144,160,1240,720,1512,320,48,4,30,96,

%U 432,1120,5040,5580,4096,1008,60,10,16,216,640,5400,6048,31992,14976,15552,2640,176

%N Array read by antidiagonals: T(n,k) = phi(k^n-1)/n, where phi is Euler's totient function (A000010), n >= 1, k >= 2.

%C For k a prime power, T(n,k) is the number of primitive polynomials of degree n over GF(k). See A011260, A027385 for additional information.

%H Andrew Howroyd, <a href="/A369291/b369291.txt">Table of n, a(n) for n = 1..1275</a> (first 50 antidiagonals)

%H Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/TotientFunction.html">Totient Function</a>.

%H Wikipedia, <a href="https://en.wikipedia.org/wiki/Euler%27s_totient_function">Euler's totient function</a>.

%e Array begins:

%e n\k| 2 3 4 5 6 7 8 9 ...

%e ---+---------------------------------------------------

%e 1 | 1 1 2 2 4 2 6 4 ...

%e 2 | 1 2 4 4 12 8 18 16 ...

%e 3 | 2 4 12 20 56 36 144 96 ...

%e 4 | 2 8 32 48 216 160 432 640 ...

%e 5 | 6 22 120 280 1240 1120 5400 5280 ...

%e 6 | 6 48 288 720 5040 6048 23328 27648 ...

%e 7 | 18 156 1512 5580 31992 37856 254016 340704 ...

%e 8 | 16 320 4096 14976 139968 192000 829440 1966080 ...

%e ...

%o (PARI) T(n,k) = eulerphi(k^n-1)/n

%Y Rows n=1..3 and 5 are A000010(k-1), A319210, A319213, A319214.

%Y Columns 2..11 are A011260, A027385, A027695, A027741, A295496, A027743, A027744, A027745, A295497, A319166.

%Y Cf. A319183.

%K nonn,tabl,easy

%O 1,4

%A _Andrew Howroyd_, Jan 28 2024

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified June 11 14:17 EDT 2024. Contains 373311 sequences. (Running on oeis4.)