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

1,1

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.

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

Table of n, a(n) for n=1..50.

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).

Formula

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

Example

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

Mathematica

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

Prog

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

Crossrefs

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

Sequence in context: A064816 A262749 A265134 * A132299 A240053 A059164

Adjacent sequences: A219997 A219998 A219999 * A220001 A220002 A220003

Keyword

nonn,easy

Author

Marc Alan Rosner, Dec 03 2012

Status

approved