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A070856
Numbers n such that sigma(reverse(n)) = phi(n).
4
1, 120, 260, 450, 861, 1411, 1541, 1550, 7372, 7957, 8393, 9312, 13811, 14840, 20440, 26060, 38323, 41550, 46990, 49813, 51412, 61050, 77695, 78625, 86691, 94604, 94632, 138631, 143520, 166331, 169360, 176820, 182750, 208150, 236220, 236840, 270650
OFFSET
1,2
LINKS
EXAMPLE
sigma(reverse(120)) = sigma(21) = 32 = phi(120), so 120 is a term of the sequence.
MATHEMATICA
Select[ Range[ 10^6 ], EulerPhi[ # ]==DivisorSigma[ 1, FromDigits[ Reverse[ IntegerDigits[ # ] ] ] ]& ]
CROSSREFS
KEYWORD
base,nonn
AUTHOR
Joseph L. Pe, May 16 2002
EXTENSIONS
Extended by Ray Chandler, Feb 10 2009
STATUS
approved