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
Hamuniverse, Handy Table for Measurements and Conversions
JGB Enterprises, Fraction-Decimal Conversion Chart
Kellog Community College, Fraction/Decimal/Conversion Chart
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
KEYWORD
nonn,easy
AUTHOR
Marc Alan Rosner, Dec 03 2012
STATUS
approved