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A058871 Sum of next n primes (A007468) is prime for odd n or half the sum is prime for even n. 0
1, 3, 5, 7, 9, 13, 18, 20, 23, 25, 29, 48, 55, 98, 117, 119, 123, 130, 173, 187, 193, 198, 205, 213, 218, 223, 248, 249, 255, 259, 265, 268, 285, 292, 299, 311, 329, 346, 351, 386, 390, 393, 397, 411, 412, 448, 483, 487, 513, 515, 525, 554, 563, 574, 587, 597 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Table of n, a(n) for n=1..56.

MATHEMATICA

Do[ s = Sum[ Prime[i], {i, n(n-1)/2 + 1, n(n+1)/2} ]; If[ PrimeQ[s] || PrimeQ[s/2], Print[n] ], {n, 10^3} ]

CROSSREFS

Cf. A007468.

Sequence in context: A228232 A182058 A200975 * A126278 A121259 A211139

Adjacent sequences:  A058868 A058869 A058870 * A058872 A058873 A058874

KEYWORD

nonn

AUTHOR

Robert G. Wilson v, Jan 06 2001

STATUS

approved

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Last modified September 24 12:23 EDT 2021. Contains 347642 sequences. (Running on oeis4.)