A085075 Smallest number a(n) == -1 (mod n) such that the prime signature of n and a(n) is the same, or 0 if no such number exists.

3, 2, 0, 19, 35, 13, 343, 0, 39, 43, 275, 103, 55, 14, 0, 67, 539, 37, 99, 62, 21, 137, 2375, 49, 51, 4913, 279, 173, 2639, 61, 28629151, 65, 33, 34, 0, 73, 265, 38, 999, 163, 1595, 257, 175, 44, 91, 281, 29375, 0, 99, 203, 207, 211, 2375, 219, 783, 341, 57, 353, 14399, 487, 123

Offset

2,1

Links

Table of n, a(n) for n=2..62.

Example

a(6) =35 = 6*6 -1 = 3*13 and 6 = 2*3 are both of prime signature p*q, where p and q are primes.

Crossrefs

Cf. A085074.

Sequence in context: A371025 A244134 A105629 * A321518 A267883 A333437

Adjacent sequences: A085072 A085073 A085074 * A085076 A085077 A085078

Keyword

nonn,changed

Author

Amarnath Murthy, Jul 01 2003

Extensions

More terms from David Wasserman, Jan 12 2005

a(32) corrected by Sean A. Irvine, May 28 2026

Status

approved