A002442 Squares written in base 9. (Formerly M3377 N1361)

1, 4, 10, 17, 27, 40, 54, 71, 100, 121, 144, 170, 207, 237, 270, 314, 351, 400, 441, 484, 540, 587, 647, 710, 764, 831, 1000, 1061, 1134, 1210, 1277, 1357, 1440, 1524, 1611, 1700, 1781, 1874, 2070, 2167, 2267, 2370, 2474, 2581, 2700, 2811, 3024, 3140, 3257

Offset

1,2

References

GCHQ, The GCHQ Puzzle Book, Penguin, 2016. See pages 108 and 300.

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).

V. Thébault, Les Récréations Mathématiques. Gauthier-Villars, Paris, 1952, p. 98.

Links

Robert Israel, Table of n, a(n) for n = 1..10000

Formula

a(n) = A007095(A000290(n)). - Jason Kimberley, Dec 13 2012

Maple

f:= proc(n) local L, i;
  L:= convert(n^2, base, 9);
  add(L[i]*10^(i-1), i=1..nops(L))
end proc:
map(f, [$1..100]); # Robert Israel, Aug 12 2018

Mathematica

Table[FromDigits[IntegerDigits[n^2, 9]], {n, 1, 100}] (* Stefan Steinerberger, Apr 11 2006 *)

Prog

(Magma) [Seqint(Intseq(n^2, 9)): n in [1..60]]; // Vincenzo Librandi, Oct 16 2015
(PARI) a(n) = fromdigits(digits(n^2, 9)); \\ Michel Marcus, Aug 13 2018

Crossrefs

Cf. A000290, A007095.

Sequence in context: A294249 A138105 A213398 * A350143 A301253 A341772

Adjacent sequences: A002439 A002440 A002441 * A002443 A002444 A002445

Keyword

nonn,base,easy

Author

N. J. A. Sloane

Extensions

More terms from Stefan Steinerberger, Apr 11 2006

Status

approved