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A066598
Numbers which can be expressed as the product of a number and its reversal in four different ways.
2
1015560, 1446480, 1854720, 10155600, 14464800, 18547200, 51665040, 59552640, 67944240, 78127560, 82623060, 88560360, 95236960, 99497160, 101556000, 105094080, 108656860, 110937960, 117681480, 118072080, 124942090, 135647680
OFFSET
1,1
MATHEMATICA
f[n_] := (m = ToExpression[StringReverse[ToString[n]]]; If[n > m, n*m, 0]); a = Sort[ Table[ f[n], {n, 0, 10^6}]]; While[ a[[1]] == 0, a = Drop[a, 1]]; a[[ Select[ Range[ Length[a]] - 3, a[[ # ]] == a[[ # + 3 ]] & ]]]
CROSSREFS
Cf. A066531.
Sequence in context: A210274 A252916 A340435 * A212940 A232144 A293127
KEYWORD
nonn
AUTHOR
Robert G. Wilson v, Jan 08 2002
STATUS
approved