cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

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

Original entry on oeis.org

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

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Author

Amarnath Murthy, Nov 17 2003

Keywords

Comments

a(17) = 181, obtained as a concatenation of 18 followed by 18 - 17 = 1.

Programs

  • 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

Extensions

Corrected and extended by C. Ronaldo (aga_new_ac(AT)hotmail.com), Dec 25 2004