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A133363 Numbers n such that 1+Sum[3k, k=1,2,...,n] is prime. 0
3, 4, 8, 11, 16, 19, 20, 23, 31, 36, 39, 44, 48, 55, 56, 68, 71, 76, 80, 83, 84, 95, 99, 103, 104, 108, 115, 116, 124, 131, 135, 139, 140, 144, 151, 156, 163, 164, 168, 171, 180, 184, 188, 191, 195, 203, 204, 215, 216, 219, 220, 223, 244, 256, 263, 268, 271, 276 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

It appears that the first differences of this sequence are never of the form 4k+2.

LINKS

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

PROG

(PARI) lista(nn) = select(n->(isprime(1+sum(k=1, n, 3*k))), vector(nn, i, i)); \\ Michel Marcus, Jul 10 2014

CROSSREFS

Cf. A067196, A134460.

Sequence in context: A287446 A051207 A217755 * A186423 A156056 A236453

Adjacent sequences:  A133360 A133361 A133362 * A133364 A133365 A133366

KEYWORD

nonn

AUTHOR

John W. Layman, Oct 26 2007

STATUS

approved

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Last modified October 17 10:07 EDT 2019. Contains 328108 sequences. (Running on oeis4.)