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A119613 Numbers n such that the difference between the largest distinct prime divisor and the smallest distinct prime divisor is a prime. 2
10, 14, 15, 20, 26, 28, 30, 35, 38, 40, 42, 45, 50, 52, 56, 60, 62, 70, 75, 76, 78, 80, 84, 86, 90, 98, 100, 104, 112, 114, 120, 122, 124, 126, 130, 135, 140, 143, 146, 150, 152, 156, 160, 168, 172, 175, 180, 182, 186, 190, 196, 200, 206, 208, 210, 218, 224, 225 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..58.

EXAMPLE

If n = 10 then the prime divisors are 2 and 5 and the difference between these two is 3 which is also a prime. So 10 is in the sequence.

If n = 70 then the prime divisors are 2, 5 and 7 and the difference between the largest and the smallest distinct prime divisors is 5 which is also a prime. So 70 is in the sequence.

MATHEMATICA

Select[Range[2, 300], Not[Length[FactorInteger[ # ]]==1]&&PrimeQ[FactorInteger[ # ][[ -1, 1]] -FactorInteger[ # ][[1, 1]]] &] (* Stefan Steinerberger, Jun 06 2006 *)

CROSSREFS

Sequence in context: A081062 A307589 A209800 * A154371 A172509 A036338

Adjacent sequences:  A119610 A119611 A119612 * A119614 A119615 A119616

KEYWORD

nonn,less

AUTHOR

Parthasarathy Nambi, Jun 05 2006

EXTENSIONS

Corrected and extended by Stefan Steinerberger, Jun 06 2006

STATUS

approved

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Last modified November 17 18:24 EST 2019. Contains 329241 sequences. (Running on oeis4.)