A233517 Record values in A061026, the smallest number m such that n divides phi(m), where phi is Euler's totient function.

1, 3, 7, 11, 29, 53, 103, 191, 311, 709, 1021, 1091, 1597, 2339, 3547, 5449, 8243, 9337, 13711, 16673, 17579, 18899, 25367, 37217, 62207, 74441, 87869, 94439, 94789, 96353, 114013, 171167, 229981, 397253, 424769, 432781, 496747, 542599, 583397, 673451, 741677

Offset: 1

Author

T. D. Noe, Feb 12 2014

Keywords

• nonn

Comments

See A233516 for the n that produce these values. After the initial 1, these numbers are prime.

Links

• Amiram Eldar, Table of n, a(n) for n = 1..101

Crossrefs

Cf. A061026, A233516.

Programs

Mathematica

t2 = {{1, 1}}; Do[k = 1; While[Mod[EulerPhi[k], n] > 0, k++]; If[k > t2[[-1,2]], AppendTo[t2, {n, k}]; Print[{n, k}]], {n, 2, 10^3}]; Transpose[t2][[2]]

PARI

lista(cmax) = {my(v = vector(cmax), c = 0, k = 1, d, vm = 0); while(c < cmax, d = divisors(eulerphi(k)); for(i = 1, #d, if(d[i] <= cmax && v[d[i]] == 0, c++; v[d[i]] = k)); k++); for(i = 1, cmax, if(v[i] > vm, vm = v[i]; print1(v[i], ", ")));} \\ Amiram Eldar, May 26 2024