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A053543 Distance to closest prime in sequence of composites. 0
1, 1, 1, 2, 1, 1, 1, 2, 1, 1, 1, 2, 1, 1, 2, 3, 2, 1, 1, 1, 2, 3, 2, 1, 1, 2, 1, 1, 1, 2, 1, 1, 2, 3, 2, 1, 1, 2, 3, 2, 1, 1, 1, 2, 3, 2, 1, 1, 2, 1, 1, 1, 2, 3, 2, 1, 1, 2, 1, 1, 2, 3, 2, 1, 1, 2, 3, 4, 3, 2, 1, 1, 2, 1, 1, 1, 2, 1, 1, 1, 2, 1, 1, 2, 3, 4, 5, 6, 7, 6, 5, 4, 3, 2, 1, 1, 2, 1, 1, 2, 3, 2, 1, 1, 1 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,4

LINKS

Table of n, a(n) for n=1..105.

FORMULA

Beginning at 2, list consecutive numbers. Measure distance of each composite to nearest prime.

EXAMPLE

Fourth composite number is 9; distance to nearest prime, 7 or 11, is 2, so a(4) = 2.

MATHEMATICA

Min[NextPrime[#]-#, #-NextPrime[#, -1]]&/@Select[Range[140], CompositeQ] (* Harvey P. Dale, Aug 31 2015 *)

CROSSREFS

Sequence in context: A115362 A277872 A161100 * A161099 A118663 A205119

Adjacent sequences:  A053540 A053541 A053542 * A053544 A053545 A053546

KEYWORD

easy,nonn

AUTHOR

Enoch Haga, Jan 16 2000

STATUS

approved

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Last modified June 17 15:28 EDT 2019. Contains 324194 sequences. (Running on oeis4.)