184458

Appears in sequences

• Number of compositions of n which are prime when concatenated and read as a decimal string.at n=21A116381
• Number of ways to build a contiguous building with n LEGO blocks of size 1 X 6 on top of a fixed block of the same size so that the building is flat, i.e., with all blocks in parallel position and symmetric after a rotation by 180 degrees.at n=10A123801