Not working for me using Pin-3 as output, both leds ON, I think the frequency is too high with those components.

https://tinyurl.com/y6l99dxx (Falstad simulation)

 

Replaced capacitor with 4.7uF electrolityc
Resistor with 100K
Blinks at 1.5Hz

(68K for 2Hz)

https://tinyurl.com/y46mmqwa (falstad simulation)

 

The Formula for calculating the Frequency is included on the Schematic,
including the original Math for the component-values in the Schematic .

It can go down to multiple-minutes, or up to approximately ~1mhz for the 7555 CMOS version .
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Thank you once again, I misunderstood your first post, I thought those were the correct values for my application.

Anyway, I've successfully implemented your suggestion. The LEDs blink very brightly, I've tested it during bike riding and they fit their purpose.

https://tinyurl.com/y4k6voen