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A227064 Primes prime(k) such that the gap prime(k-1) - prime(k-2) equals the gap prime(k+2) - prime(k+1). 1
7, 23, 37, 59, 67, 71, 73, 89, 163, 167, 233, 241, 269, 277, 367, 379, 389, 449, 479, 557, 569, 587, 599, 601, 631, 743, 751, 757, 809, 967, 983, 1009, 1033, 1039, 1109, 1117, 1229, 1283, 1297, 1307, 1361, 1439, 1523, 1559, 1607, 1609, 1613, 1637, 1669 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

This rephrases patterns of the form g, *, *, g in four successive entries of A001223, where * denotes arbitrary, not necessarily distinct, values.

The associated indices are n = 4, 9, 12, 17, 19, 20, 21, 24, 38,...

Each entry is the second next prime after A022887(n). - R. J. Mathar, Jul 12 2013

LINKS

Table of n, a(n) for n=1..49.

FORMULA

Prime(k) such that A001223(k-2) = A001223(k+1).

EXAMPLE

7 is in the sequence since the gap between the previous two primes (3 and 5) is equal to the gap between the next two primes (11 and 13).

CROSSREFS

Sequence in context: A098029 A098039 A132237 * A143030 A031043 A183126

Adjacent sequences:  A227061 A227062 A227063 * A227065 A227066 A227067

KEYWORD

nonn,less

AUTHOR

Juri-Stepan Gerasimov, Jun 30 2013

EXTENSIONS

Corrected by R. J. Mathar, Jul 12 2013

STATUS

approved

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Last modified July 13 15:18 EDT 2020. Contains 335688 sequences. (Running on oeis4.)