OFFSET
1,2
COMMENTS
For k = 6 and 9, (n+1)^k + (-n)^k is always composite (i.e. (n+1)^6 + (-n)^6 = (2*n^2+2*n+1)*(n^4+2*n^3+5*n^2+4*n+1), (n+1)^9 + (-n)^9 = (3*n^2+3*n+1)*(3*n^6+9*n^5+18*n^4+21*n^3+15*n^2+6*n+1)).
EXAMPLE
9387629 is a term because 9387630^3 - 9387629^3, 9387630^5 - 9387629^5, 9387630^7 - 9387629^7 and 9387629^2 + 9387630^2, 9387629^4 + 9387630^4, 9387629^8 + 9387630^8 are prime numbers.
CROSSREFS
KEYWORD
nonn
AUTHOR
Altug Alkan and Thomas Ordowski, Feb 27 2017
STATUS
approved