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A190148 Largest prime factor of the least number having exactly two odd prime factors that differ by 2*n^2. 0
5, 11, 23, 37, 53, 79, 101, 131, 167, 211, 271, 293, 349, 397, 457, 523, 601, 653, 727, 811, 887, 971, 1061, 1163, 1279, 1381, 1471, 1571, 1693, 1811, 1933, 2053, 2207, 2341, 2467, 2609, 2741, 2917, 3049, 3203, 3373, 3533, 3701, 3877, 4057, 4243, 4421, 4621, 4813, 5003, 5209 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

The least number having exactly two odd prime factors that differ  by 2*n^2 is given by the sequence A190052 .

LINKS

Table of n, a(n) for n=1..51.

EXAMPLE

a(11) = 271 because A190052(11) = 7859 =29 * 271 , and 271 is the largest prime

  divisor such that 271 - 29 = 242 = 2*11^2.

MAPLE

with(numtheory):for m from 1 to 60 do: k:=2*m^2:id:=0:for n from 1 to 100000

  while(id=0) do: x:=factorset(n):n1:=nops(x):n2:=bigomega(n):if n1=2 and n2=2

  and x[2]=x[1]+k then id:=1:printf(`%d, `, x[2]):else fi:od:od:

CROSSREFS

Cf. A190052.

Sequence in context: A235386 A061769 A169744 * A281875 A143125 A147081

Adjacent sequences:  A190145 A190146 A190147 * A190149 A190150 A190151

KEYWORD

nonn,easy

AUTHOR

Michel Lagneau, May 05 2011

STATUS

approved

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Last modified March 30 06:40 EDT 2020. Contains 333119 sequences. (Running on oeis4.)