A271395 Smallest prime p such that none of p - 1, p - 2, ... p - n are cubefree.

17, 137, 13313, 912251, 18035627, 148257477253, 1204244328631

Offset

1,1

Links

Table of n, a(n) for n=1..7.

Example

a(1) = 17 because 17 is prime and none of 17 - 1 = 16 = (2*2*2)*2 is cubefree; a(2) = 137 because 137 is prime and none of 137 - 1 = 136 = (2*2*2)*12, 137 - 2 = 135 = (3*3*3)*5 are cubefree: a(3) = 13313 because 13313 is prime and none of 13313 - 1 = 13312 = (2*2*2)*1664, 13313 - 2 = 13311 = (3*3*3)*493, 13313 - 3 = 13310 = (11*11*11)*10 are cubefree; a(4) = 912251 because 912251 is prime and none of 912251 - 1 = 912250 = (5*5*5)*7298, 912251 - 2 = 912249 = (3*3*3)*33787, 912251 - 3 = 912248 = (2*2*2)*114031, 912251 - 4 = 912247 = (19*19*19)*133 are cubefree.

Crossrefs

Cf. A046099, A267798.

Sequence in context: A085958 A120784 A357550 * A358202 A277387 A099922

Adjacent sequences: A271392 A271393 A271394 * A271396 A271397 A271398

Keyword

nonn,more

Author

Juri-Stepan Gerasimov, Apr 06 2016

Extensions

a(5)-a(7) from Giovanni Resta, Apr 12 2016

Status

approved