A232171 a(n) = the smallest squarefree number (A005117) with n prime factors in a prime(m) + m progression.

2, 6, 30, 61813313, 206658174154973

Offset

1,1

Comments

Let p(m) = prime(m), let i(p(m)) = m, the subscript of p(m); a(n) = the smallest squarefree number with n prime factors of the form p_1 * p_2 * p_3 * ... * p_n, where p_1 < p_2 < p_3 < ... < p_n with p_n = p_(n-1) + i(p_(n-1)).

a(6) > 10^28.

Links

Table of n, a(n) for n=1..5.

Example

206658174154973 = 521*619*733*863*1013; 619 = 521 + 98, 733 = 619 + 114, 863 = 733 + 130, 1013 = 863 + 150 (521 = 98th prime, 619 = 114th prime, 733 = 130th prime, 863 = 150th prime).

Crossrefs

Cf. A000040, A005117, A232169, A232170.

Sequence in context: A352127 A153046 A088260 * A231816 A058028 A216834

Adjacent sequences: A232168 A232169 A232170 * A232172 A232173 A232174

Keyword

nonn

Author

Jaroslav Krizek, Nov 19 2013

Status

approved