A135319 a(n) is the first digit after the decimal point in the decimal expansion of log_10(n), i.e., of the Briggsian logarithm of n.

0, 3, 4, 6, 6, 7, 8, 9, 9, 0, 0, 0, 1, 1, 1, 2, 2, 2, 2, 3, 3, 3, 3, 3, 3, 4, 4, 4, 4, 4, 4, 5, 5, 5, 5, 5, 5, 5, 5, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9

Offset: 1

Author

Pahikkala Jussi, Dec 06 2007, Jan 13 2008

Keywords

• base
• easy
• nonn

Examples

			a(6) = 7, because log_10(6) = 0.77815...
		

References

• Erwin Voellmy, Fünfstellige Logarithmen und Zahlentafeln, 15th edition, Orell Foessli Verlag, Zurich (1962).

Links

• Wikipedia, Common logarithm

Programs

Maple

A135319 := proc(n) floor(10*log[10](n)) mod 10 ; end: seq(A135319(n),n=1..80) ; # R. J. Mathar, Jan 11 2008

Formula

a(n) = floor(10*(log_10(n) - floor(log_10(n)))).

Extensions

More terms from R. J. Mathar and N. J. A. Sloane, Jan 11 2008