A181638 Numbers n such that bigomega(n) = reversal(n).

30, 40, 500, 600, 7000, 1100000, 2100000, 31000000, 810000000, 7100000000, 12000000000, 32000000000, 220000000000, 5200000000000, 7200000000000, 62000000000000, 820000000000000, 920000000000000, 13000000000000000, 5300000000000000000, 73000000000000000000, 240000000000000000000, 6400000000000000000000, 840000000000000000000000, 250000000000000000000000000, 65000000000000000000000000000

Offset

1,1

Comments

bigomega(n), also called Omega(n) is the number of prime divisors of n (counted with multiplicity) A001222.

Links

Table of n, a(n) for n=1..26.

Example

7000 is in the sequence because bigomega(7000) = reversal(7000) = 7.

Mathematica

Do[If[Plus @@ Last /@ FactorInteger[ n ] ==FromDigits[Reverse[IntegerDigits[n]]],
  Print[n]], {n, 1, 10^9}]

Crossrefs

Cf. A001222.

Sequence in context: A152616 A309306 A103250 * A166650 A275193 A225049

Adjacent sequences: A181635 A181636 A181637 * A181639 A181640 A181641

Keyword

nonn

Author

Michel Lagneau, Nov 18 2010

Extensions

a(9)-a(26) from Donovan Johnson, Nov 19 2010

Status

approved