A087019 - OEIS

%I #46 Jan 10 2019 18:34:56

%S 0,1,2,3,4,5,6,7,8,9,100,111,112,113,114,115,116,117,118,119,200,211,

%T 222,223,224,225,226,227,228,229,300,311,322,333,334,335,336,337,338,

%U 339,400,411,422,433,444,445,446,447,448,449,500,511,522,533,544,555,556,557,558

%N Lunar squares: n*n where * is lunar multiplication (A087062).

%C Sequence is not monotonic (1011*1011 = 1011111 > 1020*1020 = 1010200). In fact it even contains repetitions (11011*11011 = 11111*11111 = 111111111). See A172199. - _N. J. A. Sloane_, Dec 20 2010

%H N. J. A. Sloane, <a href="/A087019/b087019.txt">Table of n, a(n) for n = 0..10000</a>

%H D. Applegate, <a href="/A087061/a087061.txt">C program for lunar arithmetic and number theory</a>,  [Note: we have now changed the name from "dismal arithmetic" to "lunar arithmetic" - the old name was too depressing]

%H D. Applegate, M. LeBrun and N. J. A. Sloane, <a href="http://arxiv.org/abs/1107.1130">Dismal Arithmetic</a>, arXiv:1107.1130 [math.NT], 2011. [Note: we have now changed the name from "dismal arithmetic" to "lunar arithmetic" - the old name was too depressing]

%H D. Applegate, M. LeBrun, N. J. A. Sloane, <a href="https://cs.uwaterloo.ca/journals/JIS/VOL14/Sloane/carry2.html">Dismal Arithmetic</a>, J. Int. Seq. 14 (2011) # 11.9.8.

%H Brady Haran and N. J. A. Sloane, <a href="https://youtu.be/cZkGeR9CWbk">Primes on the Moon (Lunar Arithmetic)</a>, Numberphile video, Nov 2018.

%H Christian Woll, <a href="https://arxiv.org/abs/1811.04923">There is a 3X3 Magic Square of Squares on the Moon - A Lot of Them, Actually</a>, arXiv:1811.04923 [math.HO], 2018.

%H <a href="/index/Di#dismal">Index entries for sequences related to dismal (or lunar) arithmetic</a>

%F a(n)=A087062(n,n). - _M. F. Hasler_, Nov 15 2018

%o (PARI) apply( A087019(n)=A087062(n,n), [1..60]) \\ _M. F. Hasler_, Nov 15 2018

%Y Cf. A087062 (lunar product), A087097 (lunar primes).

%Y Cf. A172199, A180513, A181319, A087097.

%K nonn,base

%O 0,3

%A Marc LeBrun and _N. J. A. Sloane_, Oct 19 2003