A002942 a(n) = n^2 written backwards.

1, 4, 9, 61, 52, 63, 94, 46, 18, 1, 121, 441, 961, 691, 522, 652, 982, 423, 163, 4, 144, 484, 925, 675, 526, 676, 927, 487, 148, 9, 169, 4201, 9801, 6511, 5221, 6921, 9631, 4441, 1251, 61, 1861, 4671, 9481, 6391, 5202, 6112, 9022, 4032, 1042, 52, 1062

Offset: 1

Author

N. J. A. Sloane

Keywords

• nonn
• base
• easy
• look

Comments

a(n) = A004086(A000290(n)). - Reinhard Zumkeller, Sep 18 2013

Examples

			12*12 = 144, which written backwards is 441, so a(12) = 441.
10*10 = 100, so a(10) = 001 = 1.
		

References

• GCHQ, The GCHQ Puzzle Book, Penguin, 2016. See page 103.
• N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).
• N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

Links

• T. D. Noe, Table of n, a(n) for n = 1..1000
• Index entry for sequences related to reversing digits of squares

Crossrefs

Cf. A000290, A004086, A080334.

Programs

Haskell

a002942 = a004086 . a000290  -- Reinhard Zumkeller, Sep 18 2013

Magma

[Seqint(Reverse(Intseq(n^2))): n in [1..60]]; // Vincenzo Librandi, Sep 21 2015

Maple

a:= n-> (s-> parse(cat(s[-i]$i=1..length(s))))(""||(n^2)):
seq(a(n), n=1..60);  # Alois P. Heinz, May 20 2022

Mathematica

Table[FromDigits[Reverse[IntegerDigits[n^2]]],{n,1,40}] (* Geoffrey Critzer, Dec 04 2011 *)

Extensions

More terms from Jeremy Gardiner, Sep 08 2002