A220077 Numbers k such that 2^k + 35 is prime.

1, 3, 5, 7, 9, 11, 15, 25, 33, 57, 117, 133, 189, 195, 263, 273, 287, 509, 693, 1087, 1145, 1159, 1845, 2743, 3275, 12223, 26263, 31425, 44359, 48003, 49251, 62557, 113877, 114507, 132865, 165789, 192549, 348437, 426043, 436365, 471043, 480417

Offset: 1

Author

Vincenzo Librandi, Dec 04 2012

Keywords

• nonn

Comments

Some terms correspond to probable primes. Lifchitz link shows Lelio R Paula found the terms 132865, 165789, 192549, 348437. - Jens Kruse Andersen, Oct 01 2014

a(43) > 5*10^5. - Robert Price, Nov 01 2015

All terms are odd. - Elmo R. Oliveira, Nov 27 2023

Links

• Henri Lifchitz and Renaud Lifchitz, Search for 2^n+35, PRP Top Records.

Crossrefs

Cf. A094076, A176927.

Cf. Numbers k such that 2^k + d is prime: (0,1,2,4,8,16) for d=1; A057732 (d=3), A059242 (d=5), A057195 (d=7), A057196 (d=9), A102633 (d=11), A102634 (d=13), A057197 (d=15), A057200 (d=17), A057221 (d=19), A057201 (d=21), A057203 (d=23), A157006 (d=25), A157007 (d=27), A156982 (d=29), A247952 (d=31), A247953 (d=33), this sequence (d=35).

Programs

Mathematica

Select[Range[5000],PrimeQ[2^# + 35] &]

PARI

for(n=1, 10^30, if (isprime(2^n + 35), print1(n", "))); \\ Altug Alkan, Oct 05 2015

Extensions

a(26)-a(34) from Jens Kruse Andersen, Oct 01 2014

132865, 165789, 192549, 348437 discovered by Lelio R Paula confirmed as a(35)-a(38) by Robert Price, Oct 05 2015

a(39)-a(42) from Robert Price, Nov 01 2015