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A179675 Smallest m such that the n-th odd prime is the smallest number coprime to m and m+1. 2
1, 2, 5, 14, 209, 1364, 714, 62985, 367080, 728364, 64822394, 1306238010, 11182598504, 715041747420, 51913478860880, 454746157008780, 9314160363311804, 560934821217378530, 261062105979210899 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

A053670(a(n))=A065091(n) and A053670(m)<>A065091(n) for m<a(n).

LINKS

Table of n, a(n) for n=1..19.

EXAMPLE

n=4: a(4) = 14, A065091(4) = A053670(14) = 11,

a(4) = 14 = 2*7, a(4)+1 = 15 = 3*5;

n=5: a(5) = 209, A065091(5) = A053670(209) = 13,

a(5) = 209 = 11*19, a(5)+1 = 210 = 2*3*5*7;

n=6: a(6) = 1364, A065091(6) = A053670(1364) = 17,

a(6) = 1364 = 2*2*11*31, a(6)+1 = 1365 = 3*5*7*13.

MATHEMATICA

With[{s = Table[k = 1; While[! CoprimeQ[n, n + 1, Set[p, Prime@ k]], k++]; p, {n, 10^6}]}, Flatten@ Table[FirstPosition[s, Prime@ n], {n, 2, PrimePi@ Max@ s}]] (* Michael De Vlieger, Aug 01 2017 *)

CROSSREFS

Cf. A053670, A065091.

Sequence in context: A243979 A081483 A118478 * A193314 A270351 A240435

Adjacent sequences:  A179672 A179673 A179674 * A179676 A179677 A179678

KEYWORD

more,nonn

AUTHOR

Reinhard Zumkeller, Jul 23 2010; corrected Jul 27 2010

EXTENSIONS

a(11)-a(19) from Donovan Johnson, Jul 30 2010

STATUS

approved

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Last modified November 22 05:55 EST 2019. Contains 329388 sequences. (Running on oeis4.)