A251362 Numbers n such that n is the concatenation of distinct prime factors of phi(n), in increasing order.

25, 235741, 23517131

Offset

1,1

Comments

Next term must be greater than 10^8.

Numbers n such that n = A084317(A000010(n)). - Michel Marcus, Dec 06 2014

Links

Table of n, a(n) for n=1..3.

Example

25 is in the sequence since phi(25)=2^2*5, 235741 is in the sequence since phi(235741)=2^4*3^2*5*7*41, and 23517131 is in the sequence since phi(23517131)=2^7*3*5^2*17*131.

Mathematica

a251362[n_Integer] := Rest@ Select[Range[n], # ==
FromDigits[Flatten@IntegerDigits[First@Transpose@FactorInteger[EulerPhi[#]]]] &]; a251362[10^6] (* Michael De Vlieger, Dec 03 2014 *)

Crossrefs

Cf. A000010, A000040, A084317, A251363.

Sequence in context: A151649 A122500 A347812 * A196520 A228536 A191559

Adjacent sequences: A251359 A251360 A251361 * A251363 A251364 A251365

Keyword

nonn,base,more,bref

Author

Jahangeer Kholdi, Dec 03 2014

Status

approved