A061229 Floor of geometric mean of n and the reversal of n.

1, 2, 3, 4, 5, 6, 7, 8, 9, 3, 11, 15, 20, 23, 27, 31, 34, 38, 41, 6, 15, 22, 27, 31, 36, 40, 44, 47, 51, 9, 20, 27, 33, 38, 43, 47, 51, 56, 60, 12, 23, 31, 38, 44, 49, 54, 58, 63, 67, 15, 27, 36, 43, 49, 55, 60, 65, 70, 74, 18, 31, 40, 47, 54, 60, 66, 71, 76, 81, 22, 34, 44

Offset

1,2

Links

Harry J. Smith, Table of n, a(n) for n=1,...,2000

Formula

a(n) = floor[ {n * R(n)}^(1/2)], where R(n)= the digit reversal of n (A004086).

Example

a(15)=floor(sqrt(15*51))=floor(sqrt(765))=27.

Prog

(PARI) { default(realprecision, 100); for (n=1, 2000, x=n; r=0; while (x>0, d=x-10*(x\10); x\=10; r=r*10 + d); write("b061229.txt", n, " ", floor(sqrt(n*r))) ) } \\ Harry J. Smith, Jul 19 2009

Crossrefs

Cf. A079827.

Sequence in context: A236363 A278061 A079828 * A122666 A114288 A028899

Adjacent sequences: A061226 A061227 A061228 * A061230 A061231 A061232

Keyword

nonn,base

Author

Amarnath Murthy, Apr 23 2001

Extensions

Edited by N. J. A. Sloane, Jan 17 2009 at the suggestion of R. J. Mathar

Status

approved