A181684 Numbers n such that the sum of the cube of digits of n^n is a prime.

4, 8, 11, 29, 38, 43, 70, 74, 80, 89, 104, 112, 116, 139, 143, 166, 170, 178, 179, 182, 184, 205, 217, 223, 224, 235, 266, 271, 289, 298, 304, 322, 325, 334, 338, 344, 347, 370, 385, 392, 413, 433, 436, 454, 458, 476, 481, 487, 488, 493

Offset

1,1

Links

Table of n, a(n) for n=1..50.

Example

8 is in the sequence because 8^8= 16777216 and 1^3 + 6^3 + 7^3 + 7^3 + 7^3 + 2^3 + 1^3 + 6^3 = 1471 is a prime.

Maple

with(numtheory):for n from 1 to 500 do: l:=length(n^n) : n0:=n^n: s:=0:for
  m from 1 to l do: q:=n0:u:=irem(q, 10):v:=iquo(q, 10): n0:=v :s:=s+u^3: od:if
  type(s, prime)=true then printf(`%d, `, n):else fi:od:

Crossrefs

Sequence in context: A166550 A219747 A032819 * A126006 A164088 A109239

Adjacent sequences: A181681 A181682 A181683 * A181685 A181686 A181687

Keyword

nonn,base

Author

Michel Lagneau, Nov 17 2010

Status

approved