cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

Showing 1-3 of 3 results.

A087019 Lunar squares: n*n where * is lunar multiplication (A087062).

Original entry on oeis.org

0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 100, 111, 112, 113, 114, 115, 116, 117, 118, 119, 200, 211, 222, 223, 224, 225, 226, 227, 228, 229, 300, 311, 322, 333, 334, 335, 336, 337, 338, 339, 400, 411, 422, 433, 444, 445, 446, 447, 448, 449, 500, 511, 522, 533, 544, 555, 556, 557, 558
Offset: 0

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Author

Marc LeBrun and N. J. A. Sloane, Oct 19 2003

Keywords

Comments

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

Crossrefs

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

Programs

Formula

a(n)=A087062(n,n). - M. F. Hasler, Nov 15 2018

A180513 Lunar squares n that can be written as n = i*i in more than one way.

Original entry on oeis.org

111111111, 111111112, 111111113, 111111114, 111111115, 111111116, 111111117, 111111118, 111111119, 111111211, 111111222, 111111223, 111111224, 111111225, 111111226, 111111227, 111111228, 111111229, 111111311, 111111322, 111111333, 111111334, 111111335, 111111336, 111111337, 111111338, 111111339, 111111411, 111111422, 111111433, 111111444, 111111445, 111111446, 111111447, 111111448, 111111449, 111111511, 111111522
Offset: 1

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Keywords

Examples

			11011*11011 = 11111*11111 = 111111111.
		

Crossrefs

A172199 Number of numbers with 2n+1 digits that are lunar squares.

Original entry on oeis.org

10, 90, 900, 9000, 74667, 608673
Offset: 1

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Author

Keywords

Comments

Every lunar square (see A087019) has an odd number of digits. Lunar squares with <= 7 digits are all distinct, but for longer numbers there are many examples of pairs of numbers whose lunar squares coincide.

Crossrefs

Showing 1-3 of 3 results.