A108777 Numbers m such that a^t + b^t + c^t + ... is prime, where a*b*c* ... is the prime factorization of m with multiplicity and t is the reversal of m.

10, 40, 75, 88, 300, 500, 640, 4100, 8300

Offset

1,1

Comments

44800, 93950, 98000, 200000, 220000, 260000, and 361000 are also terms. - Michael S. Branicky, May 20 2024

Links

Table of n, a(n) for n=1..9.

Example

a(3)=75 because 75=3*5^2 and 75 reversed is 57 and 3^57 + 5^57 + 5^57 = 13877787807816026798194477932746894440813, a prime.

Mathematica

fQ[n_] := PrimeQ[Plus @@ (Flatten[ Table[ #[[1]], {#[[2]]}] & /@ FactorInteger[n]]^FromDigits[ Reverse[ IntegerDigits[ n]] ])]; Do[ If[ fQ[n], Print[n]], {n, 2200}] (* Robert G. Wilson v, Jun 28 2005 *)

Crossrefs

Cf. A082813.

Sequence in context: A104045 A102546 A352777 * A000132 A328093 A306830

Adjacent sequences: A108774 A108775 A108776 * A108778 A108779 A108780

Keyword

base,more,nonn

Author

Jason Earls, Jun 27 2005

Extensions

300, 500, 640 from Robert G. Wilson v, Jun 27 2005

4100 and 8300 from Hans Havermann, Jun 29 2005

Status

approved