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A276503
Numbers n such that phi(n) = phi(n+10), with Euler's totient function phi = A000010.
4
20, 26, 35, 100, 130, 160, 370, 400, 610, 730, 793, 1000, 1570, 1843, 1930, 2500, 2560, 2770, 2860, 3130, 3970, 4000, 4171, 4210, 4570, 5410, 5767, 6130, 6400, 6610, 6730, 7330, 7570, 8770, 9106, 9640, 9970, 9991, 10498, 10660, 10930, 11248
OFFSET
1,1
LINKS
Kevin Ford, Solutions of phi(n) = phi(n+k) and sigma(n) = sigma(n + k), arXiv:2002.12155 [math.NT], 2020.
MATHEMATICA
Select[Range[15000], EulerPhi[#] == EulerPhi[# + 10] &]
PROG
(Magma) [n: n in [1..20000] | EulerPhi(n) eq EulerPhi(n+10)];
CROSSREFS
Cf. A000010.
Cf. numbers n such that phi(n)=phi(n+k): A001274 (k=1), A001494 (k=2), A179186 (k=4), A179187 (k=5), A179188 (k=6), A179189 (k=7), A179202 (k=8), this sequence (k=10), A276504 (k=11), A217139 (k=12).
Sequence in context: A061840 A252660 A265401 * A067065 A280307 A101070
KEYWORD
nonn,easy
AUTHOR
Vincenzo Librandi, Sep 08 2016
STATUS
approved