OFFSET
1,1
COMMENTS
Subset of A051248.
LINKS
Harvey P. Dale, Table of n, a(n) for n = 1..200
EXAMPLE
2^2 = 4, 2^3 = 8, 2^4 = 16, 2^5 = 32, 2^6 = 64, 2^7 = 128, 2^8 = 256;
3^2 = 9, 3^3 = 27, 3^4 = 81, 3^5 = 243, ..., 3^18 = 387420489.
MAPLE
P:=proc(q) local b, d, k, n; for n from 1 to q do if isprime(n) then d:=ilog10(n);
for k from 2 to q do b:=ilog10(n^k); if n=trunc(n^k/10^(b-d)) then print(k);
break; fi; od; fi; od; end: P(10^6);
MATHEMATICA
sep[n_]:=Module[{len=IntegerLength[n], idn=IntegerDigits[n], exp=2}, While[ Take[ IntegerDigits[ n^exp], len] != idn, exp++]; exp]; sep/@Prime[ Range[ 60]] (* Harvey P. Dale, Jun 15 2016 *)
CROSSREFS
KEYWORD
nonn,easy,base
AUTHOR
Paolo P. Lava, May 24 2016
STATUS
approved