A089712 Smallest prime as a concatenation k and k-n.

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.

Links

Table of n, a(n) for n=1..52.

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

Adjacent sequences: A089709 A089710 A089711 * A089713 A089714 A089715

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