A059004 Smallest prime whose reversal is an n-th power.

2, 61, 521, 61, 23, 61277761, 821, 61277761, 23888027348153, 4201, 33670369817243, 61277761, 5265674839116110941, 441435249928911950281, 23888027348153, 1232787935486158110509626783, 270131

Offset

1,1

Links

Robert Israel, Table of n, a(n) for n = 1..271

Maple

revdigs:= proc(n) local L, k;
  L:= convert(n, base, 10);
  add(L[-k]*10^(k-1), k=1..nops(L))
end proc:
f:= proc(n) local d, k, wmin,  v, w;
  wmin:= infinity;
  for d from 1 do
    for k from ceil(10^(d/n)) do
      v:= k^n;
      if v >= 10^(d+1) then break fi;
      w:= revdigs(v);
      if isprime(w) and w < wmin then wmin:= w fi;
    od;
    if wmin < infinity then return wmin fi
  od
end proc:
map(f, [$1..20]); # Robert Israel, May 22 2019

Mathematica

Do[ k = 1; While[ r = ToExpression[ StringReverse[ ToString[ k^n ] ] ]; ! PrimeQ[ r ], k++ ]; Print[ r ], {n, 1, 25} ]

Crossrefs

Cf. A007488.

Sequence in context: A279624 A088078 A172230 * A297919 A298543 A298333

Adjacent sequences: A059001 A059002 A059003 * A059005 A059006 A059007

Keyword

nonn,base

Author

Robert G. Wilson v, Jan 16 2001

Status

approved