A273601 Numbers n such that (11^n - 9^n)/2 is prime.

5, 31, 271, 929, 2789, 4153

Offset

1,1

Comments

All terms are prime.

The corresponding primes: 51001, 95780952266636767336259095696501, ...

Links

Table of n, a(n) for n=1..6.

Mathematica

Select[Range[1, 10000], PrimeQ[(11^# - 9^#)/2] &]

Prog

(PARI) for(n=1, 10000, if(isprime((11^n - 9^n)/2), print1(n, ", ")))

Crossrefs

Cf. A005808, A210506, A128027, A216181, A128347, A273598, A273599, A273600, A062577.

Sequence in context: A177453 A346405 A259787 * A218679 A296967 A347416

Adjacent sequences: A273598 A273599 A273600 * A273602 A273603 A273604

Keyword

nonn,more,hard

Author

Tim Johannes Ohrtmann, May 26 2016

Status

approved