A102018 Numbers n>1 with the property that the decimal expansion of n is a permutation of the digits of the decimal expansion of phi(n) and the ratio n/phi(n) is a new record low value.

21, 291, 2817, 2991, 4435, 20617, 45421, 69271, 75841, 162619, 176569, 284029, 400399, 474883, 732031, 778669, 783169, 1014109, 1288663, 1504051, 1514419, 1924891, 1956103, 2006737, 2044501, 2094901, 2239261, 2710627, 2868469, 3582907, 3689251, 4198273, 4696009

Offset

1,1

Comments

Subsequence of A115921. - Michel Marcus, Jul 10 2015

Links

Table of n, a(n) for n=1..33.

Project Euler, Problem 70: Investigate values of n for which phi(n) is a permutation of n.

Prog

(PARI) lista(nn) = {mre = 2; for (n=2, nn, en = eulerphi(n); if (vecsort(digits(n)) == vecsort(digits(en)), re = n/en; if (re < mre, print1(n, ", "); mre = re); ); ); } \\ Michel Marcus, Jul 10 2015

Crossrefs

Cf. A000010, A115921.

Sequence in context: A022452 A183731 A101703 * A086947 A230768 A230021

Adjacent sequences: A102015 A102016 A102017 * A102019 A102020 A102021

Keyword

nonn,base

Author

Gunnar Arn Stefainsson (gos(AT)hell.is), Jun 19 2007

Extensions

More terms from Michel Marcus, Jul 10 2015

Removed initial 1 and changed definition, following discussion in Sequence Fans Mailing List by Michel Marcus and others. - N. J. A. Sloane, Jul 15 2015

Status

approved