OFFSET
1,1
COMMENTS
Numbers k such that k equals concatenation of indices of distinct prime factors of k, in increasing order.
Fixed points of A329025.
a(5) > 2.4*10^11, if it exists. - Giovanni Resta, Nov 05 2019
LINKS
EXAMPLE
2127 is a term because 2127 = 3 * 709 = prime(2) * prime(127) = concat(2, 127).
MATHEMATICA
a[n_] := FromDigits[Flatten@IntegerDigits@(PrimePi[#[[1]]] & /@ FactorInteger[n])]; Select[Range[2200], a[#] == # &]
CROSSREFS
KEYWORD
nonn,base,more
AUTHOR
Ilya Gutkovskiy, Nov 02 2019
EXTENSIONS
a(4) from Giovanni Resta, Nov 04 2019
STATUS
approved