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A060253 Numbers n such that difference between n-th prime and n-th composite number is prime. 2
1, 2, 3, 4, 7, 9, 10, 11, 13, 14, 19, 24, 25, 32, 34, 37, 60, 64, 65, 67, 71, 75, 79, 83, 87, 95, 104, 105, 111, 115, 124, 130, 132, 133, 138, 145, 152, 153, 161, 163, 166, 174, 182, 187, 188, 190, 212, 213, 217, 220, 243, 246, 251, 255, 257, 264, 275, 279, 281 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Table of n, a(n) for n=1..59.

FORMULA

Values of n such that A000040(n)-A002808(n)=p(n)-c(n) is a prime number.

EXAMPLE

n=10: p(10)=29, c(10)=18, c(10)-p(10)=11, so 10=a(7) is here.

MATHEMATICA

f[ n_Integer ] := Block[ {k = n + PrimePi[ n ] + 1}, While[ k - PrimePi[ k ] - 1 != n, k++ ]; k ]; Select[ Range[ 500 ], PrimeQ[ Prime[ # ] - f[ # ] ] & ]

CROSSREFS

Numbers n such that A038529(n) is prime. Cf. A000040, A002808.

Sequence in context: A047548 A095378 A141489 * A066276 A047340 A270711

Adjacent sequences:  A060250 A060251 A060252 * A060254 A060255 A060256

KEYWORD

easy,nonn

AUTHOR

Robert G. Wilson v, Mar 22 2001

STATUS

approved

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Last modified January 27 04:57 EST 2020. Contains 331291 sequences. (Running on oeis4.)