A067880 - OEIS

A067880

Numbers k such that phi(k) = phi(sigma(k)-k).

2, 4, 6, 10, 16, 28, 78, 114, 152, 165, 186, 222, 224, 238, 256, 402, 496, 654, 704, 738, 762, 834, 942, 1086, 1194, 1266, 1456, 1485, 1665, 1722, 1842, 1972, 2022, 2132, 2223, 2274, 2454, 2528, 2754, 2922, 2994, 3246, 3426, 3462, 3472, 3786, 4506, 4614

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OFFSET

1,1

LINKS

Amiram Eldar, Table of n, a(n) for n = 1..10000

MATHEMATICA

Select[Range[5000], EulerPhi[#] == EulerPhi[DivisorSigma[1, #] - #] &] (* Amiram Eldar, Apr 24 2022 *)

CROSSREFS

Cf. A000010, A000203, A001065, A006872.

Sequence in context: A158422 A018161 A288599 * A059749 A334213 A164142

Adjacent sequences: A067877 A067878 A067879 * A067881 A067882 A067883

KEYWORD

easy,nonn

AUTHOR

Benoit Cloitre, Mar 02 2002

STATUS

approved