A233516 - OEIS

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

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,2

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

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]]

PROG

(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

CROSSREFS

Cf. A061026, A233517.

Sequence in context: A123856 A336721 A120857 * A366029 A000043 A109799

Adjacent sequences: A233513 A233514 A233515 * A233517 A233518 A233519

KEYWORD

nonn

AUTHOR

T. D. Noe, Feb 12 2014

STATUS

approved