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A227071
Let s(m) = the set of k > 0 such that k^m ends with k. Then a(n) = least m such that s(m) = s(n).
2
1, 2, 3, 2, 5, 6, 3, 2, 9, 2, 11, 2, 5, 2, 3, 6, 17, 2, 3, 2, 21, 2, 3, 2, 9, 26, 3, 2, 5, 2, 11, 2, 33, 2, 3, 6, 5, 2, 3, 2, 41, 2, 3, 2, 5, 6, 3, 2, 17, 2, 51, 2, 5, 2, 3, 6, 9, 2, 3, 2, 21, 2, 3, 2, 65, 6, 3, 2, 5, 2, 11, 2, 9, 2, 3, 26, 5, 2, 3, 2, 81, 2
OFFSET
1,2
COMMENTS
See A227070 for more details and for the numbers n such that n = a(n).
The entries in the b-file have been tentatively obtained by comparing the terms < 10^30 in the sets s(n). - Giovanni Resta, Jul 30 2013
LINKS
Giovanni Resta, Table of n, a(n) for n = 1..10000 (warning: contains tentative terms)
FORMULA
Conjecture: a(n+1) = A132741(n) + 1. - Eric M. Schmidt, Jul 30 2013
MATHEMATICA
ts = {{}}; t2 = {1}; te = {1}; Do[s = Select[Range[0, 10^7], PowerMod[#, n, 10^IntegerLength[#]] == # &]; If[MemberQ[ts, s], AppendTo[t2, te[[Position[ts, s, 1, 1][[1, 1]]]]], AppendTo[ts, s]; AppendTo[te, n]; AppendTo[t2, n]], {n, 2, 82}]; t2
CROSSREFS
Cf. A003226 (n=2), A033819 (n=3), A068407 (n=5), A068408 (n=6).
Cf. A072496 (n=11), A072495 (n=21), A076650 (n=26).
Cf. A227070 (n such that n = a(n)).
Sequence in context: A003970 A094443 A348066 * A276270 A349668 A214571
KEYWORD
nonn,base
AUTHOR
T. D. Noe, Jul 29 2013
EXTENSIONS
Mathematica program and some entries corrected by Giovanni Resta, Jul 30 2013
STATUS
approved