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A289742 Sizes of wrenches (or spanners) using imperial units. 0
1, 4, 5, 16, 3, 8, 7, 16, 1, 2, 9, 16, 5, 8, 11, 16, 3, 4, 13, 16, 7, 8, 15, 16, 1, 1, 17, 16, 9, 8, 19, 16, 5, 4, 21, 16, 11, 8, 23, 16, 3, 2, 25, 16, 13, 8, 27, 16, 7, 4, 29, 16, 15, 8, 31, 16, 2, 1, 33, 16, 17, 8, 35, 16, 9, 4, 37, 16, 19, 8, 39, 16, 5, 2 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,2
COMMENTS
Found on sets of wrenches (US) or spanners (UK) for nut sizes in imperial units. List gives pairs (numerator, denominator) for the reduced fractions that specify the sizes.
LINKS
FORMULA
The sizes, which come in integer multiples of 1/16 inch, are equal to 4/16", 5/16", 6/16", ... but as it is customary to reduce fractions, these sizes are embossed on the wrenches as 1/4, 5/16, 3/8, .... This reduction leads to a set of numbers that are not as simple as those on metric wrenches (where the sequence is simply 6mm, 7mm, 8mm, 9mm, ...) and can make it more difficult to find the next larger or smaller wrench if the current one does not fit. So far nobody has ever been able to find the next number when I give the first 7 terms. It is similar in fun value to the clock chiming sequence A007879.
EXAMPLE
The fractions are 1/4, 5/16, 3/8, 7/16, 1/2, etc.
MATHEMATICA
{Numerator[#], Denominator[#]}&/@NestList[#+1/16&, 1/4, 50]//Flatten (* Harvey P. Dale, Oct 13 2018 *)
CROSSREFS
Cf. A007879.
Sequence in context: A119562 A289021 A323627 * A340850 A249113 A166590
KEYWORD
nonn,dumb,fini
AUTHOR
Robert Cailliau, Jul 11 2017
EXTENSIONS
More terms from Harvey P. Dale, Oct 13 2018
Edited by Jon E. Schoenfield, Jul 18 2021
STATUS
approved

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Last modified May 25 16:30 EDT 2024. Contains 372801 sequences. (Running on oeis4.)