What type of aircraft uses this long flashing pattern?
I'm assuming your question is : "What type of aircraft was it?".
Actually, we can't answer your question but you could try using Flightradar to identify the aircraft by watching a playback of the regarding time and place.

To hand you some trivia: If it was a red flashing light (the beacon) it is totally normal that the kind of flash varies. Modern aircraft use 360 degrees flashing lights (depending on the manufacturer it flashes faster or slower). Older (and most small aircraft) use rotating beacons which is just a red light shining in one direction which is turned by an motor (turns faster or slower depending on the motor).

If it was a big white light it could possibly have been the landing lights (which flash only on some aircraft) or the strobe light in the wings outer edges. They usually flash 2 times in one second and repeat the two flashes after 1 second of pause.