A114016 Least n-digit prime which differs from the next prime at every corresponding digit.

2, 19, 199, 1999, 19997, 199999, 2999999, 19999999, 199999991, 1999999973, 19999999967, 299999999989, 1999999999981, 19999999999997, 399999999999997, 1999999999999943, 49999999999999993, 199999999999999949, 1999999999999999909, 19999999999999999939

Offset

1,1

Comments

The corresponding next-primes are 3, 23, 211, 2003, 20011, 200003, 3000017, ... - Michel Marcus, Sep 15 2013

Links

Table of n, a(n) for n=1..20.

Example

1999 is a term as the next prime 2003 differs at every corresponding position (1,2), (9,0),(9,0),(9,3).

Prog

(PARI) ok(fp) = {fpa = precprime(fp); fpb = nextprime(fp); da = digits(fpa); db = digits(fpb); for (i=1, #da, if (da[i] == db[i], return (0)); ); return (fpa); }
a(n) = {if (n == 1, return (2)); for (i = 2, 9, if (p = ok(i*10^(n-1)), return(p)); ); return (0); } \\ Michel Marcus, Sep 15 2013

Crossrefs

Cf. A114017.

Sequence in context: A128970 A218117 A145104 * A268707 A037071 A126039

Adjacent sequences: A114013 A114014 A114015 * A114017 A114018 A114019

Keyword

base,nonn

Author

Amarnath Murthy, Nov 12 2005

Extensions

2 more terms from R. J. Mathar, Aug 31 2007

More terms from Michel Marcus, Sep 15 2013

Status

approved