A075028 a(1) = 1, then a(n) = the smallest number k such that the number of divisors of the n numbers from k through k+n-1 are in strictly ascending order.

1, 1, 61, 61, 11371, 11371, 7392171, 168776043, 1584614377, 38045133481, 30386250649371, 1848289766450821

Offset

1,3

Comments

tau(k) < tau(k+1) < ... < tau(k+n-1).

a(11) > 10^12. - Donovan Johnson, Oct 13 2009

a(11) > 10^13. - Giovanni Resta, Jul 25 2013

a(13) > 2.64*10^15. - Jud McCranie, Mar 27 2019

Links

Table of n, a(n) for n=1..12.

Example

a(3) = 61 = a(4) as tau(61) = 2 < tau(62) = 4 < tau(63) = 6 < tau(64) = 7.

Crossrefs

Cf. A075029, A075031.

Sequence in context: A204748 A276471 A122568 * A258158 A364715 A042859

Adjacent sequences: A075025 A075026 A075027 * A075029 A075030 A075031

Keyword

nonn,more

Author

Amarnath Murthy, Sep 02 2002

Extensions

More terms from Antonio G. Astudillo (afg_astudillo(AT)lycos.com), Apr 19 2003

a(7)-a(10) from Donovan Johnson, Oct 13 2009

a(11)-a(12) from Jud McCranie, Mar 27 2019

Status

approved