The On-Line Encyclopedia of Integer Sequences (OEIS)

Revision History for A273109

(Bold, blue-underlined text is an addition; faded, red-underlined text is a ~~deletion~~.)
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A273109

Numbers n such that in the difference triangle of the divisors of n (including the divisors of n) the diagonal from the bottom entry to n gives the divisors of n.
(history; published version)

#41 by Peter Luschny at Sat Feb 23 08:00:34 EST 2019

STATUS

reviewed

approved

#40 by Omar E. Pol at Sat Feb 23 07:26:09 EST 2019

STATUS

proposed

reviewed

#39 by Omar E. Pol at Sat Feb 23 07:25:58 EST 2019

STATUS

editing

proposed

#38 by Omar E. Pol at Sat Feb 23 07:25:33 EST 2019

CROSSREFS

Cf. A000079, A027750, A187202, A273102, A273103, A273109.

STATUS

approved

editing

Discussion

Sat Feb 23

07:25

Omar E. Pol: Removed an A-number.

#37 by Joerg Arndt at Sat Feb 23 04:30:03 EST 2019

STATUS

reviewed

approved

#36 by Michel Marcus at Sat Feb 23 03:11:29 EST 2019

STATUS

proposed

reviewed

#35 by Amiram Eldar at Sat Feb 23 02:52:32 EST 2019

STATUS

editing

proposed

#34 by Amiram Eldar at Sat Feb 23 02:48:32 EST 2019

DATA

1, 2, 4, 8, 12, 16, 32, 64, 128, 256, 512, 1024, 2048, 4096, 8192, 16384, 32768, 65536, 131072, 262144, 524288, 1048576, 2097152, 4194304, 8388608, 16777216, 33554432, 67108864, 134217728, 268435456, 536870912, 1073741824, 2147483648, 4294967296, 8589934592

MATHEMATICA

aQ[n_] := Module[{d=Divisors[n]}, nd = Length[d]; vd = d; ans = True; Do[ vd = Differences[vd]; If[Max[vd] != d[[nd-k]], ans=False; Break[]], {k, 1, nd-1}]; ans]; Select[Range[100000], aQ] (* Amiram Eldar, Feb 23 2019 *)

KEYWORD

nonn,more

nonn

EXTENSIONS

a(22)-a(35) from Amiram Eldar, Feb 23 2019

STATUS

approved

editing

Discussion

Sat Feb 23

02:52

Amiram Eldar: I run the search up to 8589934592, and still only powers of 2.

#33 by N. J. A. Sloane at Tue May 17 09:17:58 EDT 2016

STATUS

proposed

approved

#32 by Omar E. Pol at Mon May 16 16:57:43 EDT 2016

STATUS

editing

proposed