Sequence and first differences together list all positive numbers exactly once

Powers of 2 with all even digits

666 = sum(range(1,37)) and other sequences

Online Encyclopedia of Integer Sequences

The On-Line Encyclopedia of Integer Sequences

The On-Line Encyclopedia of Integer Sequences

The On-Line Encyclopedia of Integer Sequences

The On-Line Encyclopedia of Integer Sequences

Pictures from the On-Line Encyclopedia of Integer Sequences

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The On-Line Encyclopedia of Integer Sequences