A085607 Non-palindromic n and its digit reversal have the same sum of prime factors (with repetition).

45, 54, 250, 495, 594, 1131, 1311, 2262, 2550, 2622, 2750, 2926, 3393, 3933, 4154, 4489, 4514, 4545, 4636, 4995, 5454, 5808, 5994, 6292, 6364, 6550, 7800, 8085, 8749, 9478, 9844, 12441, 13980, 14269, 14421, 15167, 15180, 15602, 16237, 18449, 18977

Offset

1,1

Links

Harvey P. Dale, Table of n, a(n) for n = 1..500

Example

a(3)=250 because 250 = 2*5^3 and 52 = 2^2*13 and 2+5+5+5 = 2+2+13 = 17.

Mathematica

spf[n_]:=Total[Flatten[Table[#[[1]], #[[2]]]&/@FactorInteger[n]]]; spffQ[ n_]:=!PalindromeQ[n]&&spf[n]==spf[IntegerReverse[n]]; Select[Range[ 20000], spffQ] (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, May 19 2017 *)

Crossrefs

Cf. A001414, A085870.

Sequence in context: A039423 A043246 A044026 * A087993 A062390 A167328

Adjacent sequences: A085604 A085605 A085606 * A085608 A085609 A085610

Keyword

base,nonn

Author

Jason Earls, Jul 08 2003

Extensions

Corrected by T. D. Noe, Oct 25 2006

Status

approved