A064792 Append more digits to the n-th prime (leading zeros are permitted) until another prime is reached.

23, 31, 53, 71, 113, 131, 173, 191, 233, 293, 311, 373, 419, 431, 479, 5303, 593, 613, 673, 719, 733, 797, 839, 8923, 971, 1013, 1031, 10709, 1091, 11311, 1277, 1319, 1373, 1399, 1493, 1511, 1571, 1637, 16703, 1733, 17903, 1811, 1913, 1931, 1973

Offset: 1

Author

Reinhard Zumkeller, Oct 17 2001

Keywords

• nonn
• base

Comments

Differs from A030670 in that here the appended digits may start with 0 which is not possible there (although zeros are allowed there, too, if they are not the first appended digit): The first difference appears at a(16) = 5303 where A030670(16) = 5323. - M. F. Hasler, Jan 15 2025

Links

• Daniel Mondot, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A030665.

See A030670 for another version. Note that A030670 >= a(n). Cf. A065112.

Programs

PARI

apply( {A064792(n)=n=prime(n);for(L=1,oo, n*=10; forstep(s=1,10^L-1,2, isprime(n+s)&& return(n+s)))}, [1..44]) \\ M. F. Hasler, Jan 15 2025

Formula

a(n) = A030665(prime(n)). - Michel Marcus, Jan 17 2025