A241197 Numerator of new minima of phi(p-1)/(p-1), where phi is Euler's totient function and p = prime(n).

1, 1, 1, 4, 8, 16, 288, 256, 192, 768, 384, 3456, 3072, 6912, 6144, 55296, 1658880, 221184, 110592, 3317760, 442368, 13271040

Offset

1,4

Comments

The values of p are in A241196. The denominator is in A241198.

Links

Table of n, a(n) for n=1..22.

Example

In decimal, the minima are about 1, 0.5, 0.333333, 0.266667, 0.228571, 0.207792, 0.196856, 0.195569, 0.191808, 0.185194, 0.183469, 0.181713, 0.180525, 0.173812, 0.172676, 0.171024, 0.165507, 0.165127, 0.163588.

Mathematica

tMin = {{2, 1}}; Do[p = Prime[n]; tn = EulerPhi[p - 1]/(p - 1); If[tn < tMin[[-1, -1]], AppendTo[tMin, {p, tn}]], {n, 10^7}]; Numerator[Transpose[tMin][[2]]]

Crossrefs

Cf. A008330 (phi(prime(n)-1)), A073918, A241194, A241195.

Sequence in context: A242966 A337235 A038110 * A130436 A260306 A031462

Adjacent sequences: A241194 A241195 A241196 * A241198 A241199 A241200

Keyword

nonn,frac,more

Author

T. D. Noe, Apr 17 2014

Extensions

a(20)-a(22) from Giovanni Resta, Apr 14 2016

Status

approved