A233516 Where records occur in A061026, the smallest number m such that n divides phi(m), where phi is Euler's totient function.

1, 2, 3, 5, 7, 13, 17, 19, 31, 59, 85, 109, 133, 167, 197, 227, 317, 389, 457, 521, 799, 859, 1153, 1163, 1637, 1861, 1997, 2053, 2633, 3011, 3167, 3721, 3833, 5227, 6637, 7213, 9199, 12919, 13259, 13469, 14263

Offset: 1

Author

T. D. Noe, Feb 12 2014

Keywords

• nonn

Comments

Not all of these numbers are prime. The record values are in A233517.

Links

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

Crossrefs

Cf. A061026, A233517.

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][[1]]

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(i, ", ")));} \\ Amiram Eldar, May 26 2024