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A115893 Numbers k such that sigma(k)*prime(k) is a palindrome. 1
1, 2, 5, 4813, 47619 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,2
COMMENTS
No additional terms up to 5*10^6. - Harvey P. Dale, Sep 14 2012
LINKS
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
Sequence in context: A306747 A187604 A082815 * A323338 A057678 A090071
KEYWORD
nonn,base
AUTHOR
Giovanni Resta, Feb 06 2006
STATUS
approved

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Last modified May 18 15:02 EDT 2024. Contains 372641 sequences. (Running on oeis4.)