A220000 Sixty fourths of an inch in thousandths, rounded to nearest integer.

16, 31, 47, 63, 78, 94, 109, 125, 141, 156, 172, 188, 203, 219, 234, 250, 266, 281, 297, 313, 328, 344, 359, 375, 391, 406, 422, 438, 453, 469, 484, 500, 516, 531, 547, 563, 578, 594, 609, 625, 641, 656, 672, 688, 703, 719, 734, 750, 766, 781

Offset: 1

Author

Marc Alan Rosner, Dec 03 2012

Keywords

• nonn
• easy

Comments

Diameter of successive drill bits, in thousandths of an inch, within an ordered set consisting of increments of 1/64th of an inch. Traditionally the sizes of bits in such a set are expressed in simplest reduced fractional inch values: 1/64, 1/32, 3/64, 1/16, etc. Of fundamental importance to machinists, tool and die makers, carpenters, hobbyists, insomnial science teachers, etc.

Examples

			For n = 5 the a(5) term = (5/64)*1000 = 78.125, which is rounded to 78.
		

References

• Jack Erjavec, Automotive Technology, 2010, pages 66-73.
• Frank D. Graham, Audels Machinists and Tool Makers Handy Book, 1941, pages 34-48.
• IBM Corp., Precision Measurement in the Metal Working Industry, 1939, page 11.

Links

• Hamuniverse, Handy Table for Measurements and Conversions
• JGB Enterprises, Fraction-Decimal Conversion Chart
• Kellog Community College, Fraction/Decimal/Conversion Chart
• Moam, Inc., Decimal Equivalents: Fractions-Inches-Millimeters-Points
• Index entries for linear recurrences with constant coefficients, signature (1,0,0,0,0,0,0,1,-1).

Crossrefs

Cf. A085269, A029919, A029920, A169860, A169861.

Programs

Mathematica

Table[Floor[1000 n/64+1/2],{n,64}] (* Harvey P. Dale, Jan 13 2020 *)

PARI

a(n)=(125*n+4)\8 \\ Charles R Greathouse IV, Dec 06 2012

Formula

a(n) = round(125*n/8), with 0.5 rounded up.