A243093 Least number k > n such that n concatenated with k is a perfect power.

6, 5, 6, 9, 12, 25, 29, 41, 61, 24, 56, 25, 31, 44, 21, 81, 28, 49, 36, 25, 87, 201, 104, 336, 281, 244, 44, 224, 241, 276, 36, 49, 64, 81, 344, 100, 249, 44, 69, 96, 209, 436, 56, 89, 369, 225, 61, 400, 284, 176, 84, 441, 361, 76, 225, 169, 76, 564, 319, 84, 504, 500, 504, 516, 536, 564

Offset: 1

Author

Derek Orr, Aug 18 2014

Keywords

• nonn
• base

Links

• Harvey P. Dale, Table of n, a(n) for n = 1..1000

Crossrefs

Cf. A245632.

Programs

Mathematica

pp[n_]:=Module[{k=n+1},While[GCD@@FactorInteger[n*10^IntegerLength[ k]+ k][[All,2]]<2,k++];k]; Array[pp,70] (* Harvey P. Dale, Oct 09 2016 *)

PARI

a(n)=s=Str(n);k=n+1;while(!ispower(eval(concat(s,Str(k)))),k++);return(k)
vector(100,n,a(n))

Python

from sympy import perfect_power
def a(n):
    s, k = str(n), n+1
    while not perfect_power(int(s+str(k))): k += 1
    return k
print([a(n) for n in range(1, 67)]) # Michael S. Branicky, Jun 05 2021