login
A089712
Smallest prime as a concatenation k and k-n.
2
11, 43, 31, 41, 73, 61, 71, 103, 113, 101, 199, 3019, 131, 163, 151, 227, 193, 181, 191, 223, 211, 3413, 3917, 241, 251, 283, 271, 281, 313, 367, 311, 409, 331, 5623, 373, 383, 5519, 5417, 457, 401, 433, 421, 431, 463, 6521, 461, 5711, 503, 491, 523, 577, 521
OFFSET
1,1
COMMENTS
a(17) = 181, obtained as a concatenation of 18 followed by 18 - 17 = 1.
MAPLE
ds:=proc(s) local j: RETURN(add(s[j]*10^(j-1), j=1..nops(s))): end: a:=proc(n) local k, m: for k from n+1 do m:=ds([op(convert(k-n, base, 10)), op(convert(k, base, 10))]): if isprime(m) then RETURN(m) fi od: end: seq(a(n), n=0..60); # C. Ronaldo
CROSSREFS
Sequence in context: A156533 A228811 A096638 * A359664 A155711 A226617
KEYWORD
base,nonn
AUTHOR
Amarnath Murthy, Nov 17 2003
EXTENSIONS
Corrected and extended by C. Ronaldo (aga_new_ac(AT)hotmail.com), Dec 25 2004
STATUS
approved