A257035 Numbers m such that 6m+1, 12m+1, 18m+1, 36m+1 and 72m+1 are all prime.

1, 121, 380, 506, 511, 3796, 5875, 6006, 8976, 9025, 9186, 10920, 12245, 12896, 14476, 14800, 15386, 22451, 23471, 32326, 35175, 38460, 39536, 40420, 41456, 43430, 44415, 59901, 60076, 61341, 74676, 76615, 76986, 82530, 87390, 99486, 101101, 107926, 112315, 112840, 115101

Offset

1,2

Comments

A subsequence of A206024, which contains A206349 as a subsequence, see there for motivations.

Links

Amiram Eldar, Table of n, a(n) for n = 1..10000 (terms 1..1000 from Harvey P. Dale)

Maple

f:=isprime: select(m->f(6*m+1) and f(12*m+1) and f(18*m+1) and f(36*m+1) and f(72*m+1), [$1..120000] ); # Muniru A Asiru, Jun 06 2018

Mathematica

Select[Range[120000], PrimeQ[6 # + 1] && PrimeQ[12 # + 1] && PrimeQ[18 # + 1] && PrimeQ[36 # + 1] && PrimeQ[72 # + 1] &] (* Vincenzo Librandi, Apr 15 2015 *)
Select[Range[120000], AllTrue[{6, 12, 18, 36, 72}#+1, PrimeQ]&] (* The program uses the AllTrue function from Mathematica version 10 *) (* Harvey P. Dale, Oct 23 2016 *)

Prog

(PARI) is(m, c=72)=!until(bittest(c\=2, 0)&&9>c+=3, isprime(m*c+1)||return)
(Magma) [n: n in [0..2*10^5] | IsPrime(6*n+1) and IsPrime(12*n+1) and IsPrime(18*n+1) and IsPrime(36*n+1)and IsPrime(72*n+1)]; // Vincenzo Librandi, Apr 15 2015
(GAP) Filtered([1..120000], m->IsPrime(6*m+1) and IsPrime(12*m+1) and IsPrime(18*m+1) and IsPrime(36*m+1) and IsPrime(72*m+1)); # Muniru A Asiru, Jun 06 2018

Crossrefs

Cf. A002997, A112428, A174613, A206024, A206349.

Sequence in context: A330670 A253321 A253328 * A128608 A326710 A144719

Adjacent sequences: A257032 A257033 A257034 * A257036 A257037 A257038

Keyword

nonn,easy,changed

Author

M. F. Hasler, Apr 14 2015

Status

approved