A225582 Primes in the chain of repeated application of x->2*x+3, starting at x=11.

11, 53, 109, 1789, 3581, 28669, 229373, 3670013, 58720253, 117440509, 60129542141, 264452523040700131966973, 34662321099990647697175478269, 2381976568446569244243622252022377480189, 4878288012178573812210938372141829079433213

Offset

1,1

Comments

Primes in A156127.

Links

Vincenzo Librandi, Table of n, a(n) for n = 1..26

Mathematica

Select[NestList[2 # + 3 &, 11, 30], PrimeQ] (* or *) Select[Table[7 2^n - 3, {n, 0, 150}], PrimeQ]

Prog

(Magma) x:=11; a:=[n eq 1 select x else 2*Self(n-1)+3: n in [1..200]]; [a[i]: i in [1..#a] | IsPrime(a[i])]; /* or */ [a: n in [0..150] | IsPrime(a) where a is 7*2^n-3];

Crossrefs

Primes of the form k*2^m-3: A050415 (k=1), A173769 (k=5), this sequence (k=7), A225583 (k=11), A225584 (k=13); A172156 (k=100), A163589 (k=715).

Numbers of the form 7*2^m-3: A156127.

Sequence in context: A045471 A086715 A178453 * A164580 A141893 A093198

Adjacent sequences: A225579 A225580 A225581 * A225583 A225584 A225585

Keyword

nonn,easy

Author

Vincenzo Librandi, May 14 2013

Status

approved