A074452 - OEIS

A074452

Treated as strings, phi(n) is a substring of sigma(n).

1, 6, 60, 84, 112, 141, 168, 252, 270, 294, 450, 570, 1188, 1320, 2376, 2436, 2508, 4584, 5016, 5406, 6426, 7110, 8850, 13566, 14270, 15834, 17416, 23320, 31152, 34452, 58520, 62568, 72732, 75210, 79035

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OFFSET

1,2

LINKS

Harvey P. Dale, Table of n, a(n) for n = 1..100

EXAMPLE

phi(84) = 24, a substring of sigma(24) = 224, so 84 is a term of the sequence.

MATHEMATICA

r = {}; Do[If[StringPosition[ToString[DivisorSigma[1, i]], ToString[EulerPhi[i]]] != {}, r = Append[r, i]], {i, 1, 10^5}]; r

psQ[n_]:=Module[{ep=IntegerDigits[EulerPhi[n]], ds=IntegerDigits[ DivisorSigma[ 1, n]]}, MemberQ[Partition[ds, Length[ep], 1], ep]]; Select[Range[80000], psQ] (* Harvey P. Dale, Dec 15 2014 *)

CROSSREFS

Sequence in context: A335937 A136937 A295829 * A168618 A185288 A189000

Adjacent sequences: A074449 A074450 A074451 * A074453 A074454 A074455

KEYWORD

base,nonn

AUTHOR

Joseph L. Pe, Sep 25 2002

STATUS

approved