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A209618 Primes separated from their adjacent next primes by a composite number of successive composites. 2
139, 181, 241, 283, 337, 409, 421, 547, 577, 631, 691, 709, 787, 811, 829, 919, 1021, 1039, 1051, 1129, 1153, 1171, 1249, 1327, 1399, 1471, 1627, 1699, 1723, 1801, 1831, 1879, 1933, 1951, 2017, 2029, 2053, 2089, 2113, 2143, 2221, 2251, 2311, 2477, 2521, 2557 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

a(1) = 139 is the first prime separated from the next prime (149) by a composite number (9) of successive composites, namely, 140, 141, 142, 143, 144, 145, 146, 147, 148.

LINKS

Table of n, a(n) for n=1..46.

MATHEMATICA

ps = Prime[Range[500]]; pos = Position[Differences[ps] - 1, _?(# > 1 && ! PrimeQ[#] &)]; ps[[Flatten[pos]]] (* T. D. Noe, Mar 21 2012 *)

CROSSREFS

Cf. A209619.

Sequence in context: A050967 A071382 A290450 * A031928 A095649 A016067

Adjacent sequences:  A209615 A209616 A209617 * A209619 A209620 A209621

KEYWORD

nonn

AUTHOR

Lekraj Beedassy, Mar 21 2012

STATUS

approved

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Last modified July 26 20:28 EDT 2021. Contains 346295 sequences. (Running on oeis4.)