A115893 Numbers k such that sigma(k)*prime(k) is a palindrome.

1, 2, 5, 4813, 47619

Offset

1,2

Comments

No additional terms up to 5*10^6. - Harvey P. Dale, Sep 14 2012

Links

Table of n, a(n) for n=1..5.

Example

sigma(47619)*prime(47619) = 82992*580477 = 48174947184.

Mathematica

dspQ[n_]:=Module[{c=IntegerDigits[DivisorSigma[1, n]Prime[n]]}, c == Reverse[c]]; Select[Range[50000], dspQ] (* Harvey P. Dale, Sep 14 2012 *)

Crossrefs

Cf. A084122, A115890, A115894.

Sequence in context: A306747 A187604 A082815 * A323338 A057678 A090071

Adjacent sequences: A115890 A115891 A115892 * A115894 A115895 A115896

Keyword

nonn,base

Author

Giovanni Resta, Feb 06 2006

Status

approved