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A270639 Fermat pseudoprimes (A001567) that are the sum of three consecutive primes. 1
13741, 16705, 150851, 208465, 249841, 252601, 258511, 410041, 486737, 635401, 1052503, 1082401, 1457773, 1507963, 1579249, 1615681, 2113921, 2184571, 3090091, 3375487, 3726541, 4682833, 4895065, 5044033, 5133201, 6233977, 6255341, 6350941, 6474691, 6912079, 7259161 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

In other words, Fermat pseudoprimes to base 2 of the form p + q + r where p, q and r are consecutive primes.

If a Fermat pseudoprime is the sum of n consecutive primes, it is so obvious that the minimum value of n is 3.

Intersection of A001567 and A034961.

LINKS

Amiram Eldar, Table of n, a(n) for n = 1..10000

EXAMPLE

4567, 4583 and 4591 are consecutive primes and their sum is 13741, a Fermat pseudoprime.

84191, 84199 and 84211 are consecutive primes and their sum is 252601, a Fermat pseudoprime.

PROG

(PARI) isA001567(n) = {Mod(2, n)^n==2 && !ispseudoprime(n) && n > 1}

a034961(n) = my(p=prime(n), q=nextprime(p+1)); p+q+nextprime(q+1);

for(n=1, 200000, if(isA001567(a034961(n)), print1(a034961(n), ", ")));

CROSSREFS

Cf. A001567, A034961, A270267.

Sequence in context: A236708 A205259 A235184 * A031807 A119730 A204839

Adjacent sequences:  A270636 A270637 A270638 * A270640 A270641 A270642

KEYWORD

nonn

AUTHOR

Altug Alkan, Mar 20 2016

STATUS

approved

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Last modified February 26 11:40 EST 2020. Contains 332279 sequences. (Running on oeis4.)