OFFSET
1,1
COMMENTS
a(2n)=a(5n)=0. Next term a(17) has 176 digits (k=16) and is too large to include in sequence. a(19), if it exists, has k>100. - Ray Chandler, Oct 18 2003
EXAMPLE
a(11) = 111121 which is a concatenation of 1, 11 and 121. value of k = 2.
MATHEMATICA
f[n_] := Block[{k = FromDigits[Join[{1}, IntegerDigits[n]]], e = 1}, While[ !PrimeQ[k], e++; k = FromDigits[Join[IntegerDigits[k], IntegerDigits[n^e]]]]; k]; g[n_] := If[ Mod[n, 10] == 1 || Mod[n, 10] == 3 || Mod[n, 10] == 7 || Mod[n, 10] == 9, f[n], 0]; Table[ g[n], {n, 1, 17}] (* Robert G. Wilson v *)
CROSSREFS
KEYWORD
base,nonn
AUTHOR
Amarnath Murthy, Oct 17 2003
STATUS
approved