login
A280895
For any n>=0, least prime k = p^d-2*n, where p is a prime and d is its number of digits.
1
2, 3, 3, 163, 113, 1030291, 109, 107, 2571337, 103, 101, 2248069, 97, 263, 1442869, 139, 89, 1225009, 2685583, 83, 2571313, 79, 317, 2571307, 73, 71, 1224991, 67, 113, 3307891, 61, 59, 104633567005988371387, 103, 53, 1224973, 97, 47, 1224967, 43, 41, 1030219, 37
OFFSET
0,1
LINKS
EXAMPLE
a(5) = 1030291 because 1030291 is the least prime such that 101^3 - 2*5 = 1030301 - 10 = 1030291.
MAPLE
P:=proc(q) local a, b, k, n; for n from 0 to q do for k from 1 to q do a:=ithprime(k);
b:=a^(ilog10(a)+1)-2*n; if isprime(b) then lprint(n, b); break; fi; od; od; end: P(1000);
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Paolo P. Lava, Jan 10 2017
STATUS
approved