The On-Line Encyclopedia of Integer Sequences (OEIS)

Revision History for A216836

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A216836

Numbers n such that sum of decimal digits of n divides phi(n).
(history; published version)

#31 by Charles R Greathouse IV at Thu Sep 08 08:46:03 EDT 2022

PROG

(MAGMAMagma) [n: n in [1..1000] | IsIntegral((EulerPhi(n))/&+Intseq(n))]; // Marius A. Burtea, Dec 20 2018

Discussion

Thu Sep 08

08:46

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

#30 by OEIS Server at Thu Dec 20 23:55:06 EST 2018

LINKS

Marius A. Burtea and Muniru A Asiru, <a href="/A216836/b216836_1.txt">Table of n, a(n) for n = 1..10000</a> (first 3028 terms from Marius A. Burtea)

#29 by N. J. A. Sloane at Thu Dec 20 23:55:06 EST 2018

STATUS

proposed

approved

Discussion

Thu Dec 20

23:55

OEIS Server: Installed new b-file as b216836.txt.  Old b-file is now b216836_1.txt.

#28 by Robert Israel at Thu Dec 20 23:42:27 EST 2018

STATUS

editing

proposed

#27 by Robert Israel at Thu Dec 20 23:16:18 EST 2018

COMMENTS

If n is in the sequence, then so is 10*n. - Robert Israel, Dec 20 2018

MAPLE

select(n -> numtheory:-phi(n) mod convert(convert(n, base, 10), `+`) = 0, [$1..1000]); # Robert Israel, Dec 20 2018

STATUS

proposed

editing

#26 by Muniru A Asiru at Thu Dec 20 17:49:25 EST 2018

STATUS

editing

proposed

Discussion

Thu Dec 20

17:50

Michel Marcus: I don't get any output with gap?

18:08

Daniel Suteu: The "Print(a);" statement needs to be added at the end of the GAP program. See: https://tio.run/##S08s@P8/LzexwsrW0NTA2por2MrWJ7O4RANMRBvq6YEkY3UU8nTtQEL@aS6Z6ZklxRp5mpo6CsGluZrW1goBUD2oygMyMkGqgGYmWtm6ZeaUpBalpiCryQSqic6MVcjNT1EIBjJsDTSBZhVl5pVoJGpa//8PAA

#25 by Muniru A Asiru at Thu Dec 20 17:48:56 EST 2018

LINKS

Marius A. Burtea, and Muniru A Asiru, <a href="/A216836/b216836_1.txt">Table of n, a(n) for n = 1..10000</a> (first 3028</a> terms from Marius A. Burtea)

STATUS

proposed

editing

#24 by Muniru A Asiru at Thu Dec 20 17:39:30 EST 2018

STATUS

editing

proposed

#23 by Muniru A Asiru at Thu Dec 20 17:39:14 EST 2018

PROG

(GAP) nmax:=150;;

S:=List(List([1..nmax], n->ListOfDigits(n)), Sum);; P:=List([1..nmax], n->Phi(n));;

a:=Filtered([1..nmax], i->P[i] mod S[i]=0); # Muniru A Asiru, Dec 20 2018

STATUS

proposed

editing

#22 by Michel Marcus at Thu Dec 20 14:27:43 EST 2018

STATUS

editing

proposed