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A061229
Floor of geometric mean of n and the reversal of n.
3
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
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
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