A105525 Smallest prime forming a product of n distinct primes when a 1 is appended to it.

3, 2, 23, 821, 14387, 131231, 4976687, 87200213, 6746125577, 121926946241, 5509396663871, 254605525405331, 12690278491719929, 565269607109838731, 32485826999091637271, 2154833052882128071553, 156066104202356713394129

Offset

1,1

Links

Table of n, a(n) for n=1..17.

Example

We have a(2)=2 because 2 is the first prime ahead of 5,11,29,37,... each becoming a product of two distinct primes with an appended 1.

Prog

(PARI) {r(n, p, d)=local(q); if(d==0, if(n%10==1 && isprime(n\10) && n<m, m=n); return); q=nextprime(p+1); while(n*q^d<m, r(n*q, q, d-1); q=nextprime(q+1))} {A105526(d) = M=2^16; while(1, m=M; r(1, 2, d); if(m!=M, return(m\10)); M*=2)} (Alekseyev)

Crossrefs

Cf. A105526.

Sequence in context: A151429 A355290 A151475 * A228772 A165714 A090883

Adjacent sequences: A105522 A105523 A105524 * A105526 A105527 A105528

Keyword

nonn,base

Author

Lekraj Beedassy, Apr 11 2005

Extensions

a(5)-a(8) from Ray Chandler, Apr 16 2005

More terms from Max Alekseyev, Apr 28 2005

Status

approved