The On-Line Encyclopedia of Integer Sequences (OEIS)

Revision History for A248795

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A248795

Numbers n such that Product_{d|n} phi(d) = Product_{d|(n+1)} phi(d) where phi(x) = Euler totient function (A000010).
(history; published version)

#29 by Charles R Greathouse IV at Thu Sep 08 08:46:10 EDT 2022

PROG

(MAGMAMagma) [n: n in [1..100000] | (&*[EulerPhi(d): d in Divisors(n)]) eq (&*[EulerPhi(d): d in Divisors(n+1)])]

Discussion

Thu Sep 08

08:46

OEIS Server: https://oeis.org/edit/global/2944

#28 by N. J. A. Sloane at Thu Dec 04 23:42:32 EST 2014

STATUS

proposed

approved

#27 by Jon E. Schoenfield at Sun Nov 30 19:59:53 EST 2014

STATUS

editing

proposed

Discussion

Tue Dec 02

12:54

R. J. Mathar: Of course A248796 should be recycled if this here is accepted...

#26 by Jon E. Schoenfield at Sun Nov 30 19:59:30 EST 2014

COMMENTS

4294967295 is also term of in this sequence.

STATUS

proposed

editing

Discussion

Sun Nov 30

19:59

Jon E. Schoenfield: Does this change look okay?

#25 by Michael De Vlieger at Sun Nov 30 16:29:18 EST 2014

STATUS

editing

proposed

#24 by Michael De Vlieger at Sun Nov 30 16:28:47 EST 2014

MATHEMATICA

a248795[n_Integer] := Select[Range[n],

Product[EulerPhi[i], {i, Divisors[#]}] ==

Product[EulerPhi[j], {j, Divisors[# + 1]}] &]; a248795[10^5] (* Michael De Vlieger, Nov 30 2014 *)

STATUS

proposed

editing

Discussion

Sun Nov 30

16:29

Michael De Vlieger: added mma

#23 by Jon E. Schoenfield at Fri Nov 28 04:10:32 EST 2014

STATUS

editing

proposed

#22 by Jon E. Schoenfield at Fri Nov 28 04:10:29 EST 2014

EXAMPLE

Number 15 is in the sequence because A029940(15) = A029940(16) = 64.

STATUS

reviewed

editing

#21 by Michel Marcus at Tue Nov 25 05:30:20 EST 2014

STATUS

proposed

reviewed

#20 by Michel Marcus at Sun Nov 23 16:18:07 EST 2014

STATUS

editing

proposed