OFFSET
1,3
LINKS
Giovanni Resta, Table of n, a(n) for n = 1..61
Cristian Cobeli, DOI^2, arXiv:1911.09003 [math.HO], 2019. See Table 2 p. 7.
Cristian Cobeli, DOI^2, Romanian Journal Of Pure And Applied Mathematics, Tome LXVI, No. 3-4, 2021.
EXAMPLE
For k=1 to 9, k^k has k digits, that is, A066022(k) is a repdigit.
k=631296394 is a term since k^k has 5555555555 digits. See Cobeli link.
MATHEMATICA
Flatten@ Reap[Sow[0]; Do[v = d (10^nd-1)/9; s = Solve[v-1 <= x Log10[x] < v, x, Integers]; If[s != {}, Sow[x /. s]], {nd, 15}, {d, 9}]][[2, 1]] (* Giovanni Resta, Dec 05 2019 *)
PROG
(PARI) isok(k) = #Set(digits(#Str(k^k))) == 1;
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Michel Marcus, Dec 05 2019
EXTENSIONS
a(28)-a(42) from Giovanni Resta, Dec 05 2019
STATUS
approved