Eighteen

 Had an interesting dream last night regarding the number 18, probably thanks to the trataka meditation over the Sigillum Dei.

This is what I found out about number 18:

• The Hebrew word for life (chai) has a numeric value of 18
• Shemoneh Esrei is a type of prayer (the name means eighteen)
• 18 is a heptagonal number. Heptagonal numbers are numbers that are constructed by combining heptagons with ascending sizes.

Regarding the heptagonal number, if we take the following formula:

if we replace n with the number 3, we will get (5*3^2 - 3*3)/2, which is 18. Which means 18 is the third heptagonal number. A bit more interesting when we consider that Sigillum Dei commonly contains 3 heptagons.

Anyway, I need to delve deeper into the Shemoneh Esrei, I checked the first part of the prayer so far and it does seem interesting.