A087093 Numbers that have the same number of divisors as their digit reversal, but with different prime signatures.

24, 42, 264, 288, 462, 658, 856, 882, 1071, 1128, 1314, 1464, 1701, 2058, 2130, 2132, 2312, 2324, 2424, 2510, 2590, 2616, 2664, 2744, 2765, 2782, 2786, 2872, 2904, 2938, 2975, 3159, 3194, 4010, 4090, 4092, 4094, 4125, 4131, 4136, 4168, 4184, 4220, 4228

Offset

1,1

Comments

Terms in A062895 but not in A085869.

Links

Amiram Eldar, Table of n, a(n) for n = 1..10000

Example

24 and 42 are members as 24 and 42 each have 8 divisors but with different prime signatures.

Mathematica

psQ[n_]:=Sort[Transpose[FactorInteger[n]][[2]]]!=Sort[Transpose[ FactorInteger[FromDigits[Reverse[IntegerDigits[n]]]]][[2]]]; ndQ[n_]:= DivisorSigma[0, n]==DivisorSigma[0, FromDigits[Reverse[ IntegerDigits[ n]]]]; Select[Range[5000], psQ[#]&&ndQ[#]&] (* Harvey P. Dale, Nov 11 2011 *)

Crossrefs

Cf. A000005, A062895, A085869, A085870.

Sequence in context: A039411 A043234 A044014 * A118299 A302360 A258865

Adjacent sequences: A087090 A087091 A087092 * A087094 A087095 A087096

Keyword

nonn,base

Author

Ray Chandler, Aug 09 2003

Status

approved