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# 225

Please do not rely on any information it contains.

225 is the square of 15. It is only the second number to be both square and octagonal, the first is 1 (see A036428)

## Membership in core sequences

 Odd numbers ..., 219, 221, 223, 225, 227, 229, 231, ... A005408 Composite numbers ..., 221, 222, 224, 225, 226, 228, 230, ... A002808 Perfect squares ..., 144, 169, 196, 225, 256, 289, 324, ... A000290

## Sequences pertaining to 225

 Multiples of 225 225, 450, 675, 900, 1125, 1350, 1575, 1800, 2025, 2250, 2475, 2700, ... Divisors of 225 1, 3, 5, 9, 15, 25, 45, 75, 225 A018342

## Partitions of 225

There are X partitions of 225.

## Roots and powers of 225

In the table below, irrational numbers are given truncated to eight decimal places.

TABLE GOES HERE

## Logarithms and 225th powers

In the OEIS specifically and mathematics in general, ${\displaystyle \log x}$ refers to the natural logarithm of ${\displaystyle x}$, whereas all other bases are specified with a subscript.

As above, irrational numbers in the following table are truncated to eight decimal places.

TABLE GOES HERE

TABLE GOES HERE

## Factorization of 225 in some quadratic integer rings

As was mentioned above, 225 is the product of 3 2 and 5 2. But it has different factorizations in some quadratic integer rings.

TABLE GOES HERE

## Representation of 225 in various bases

 Base 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 Representation 11100001 22100 3201 1400 1013 441 341 270 225 195 169 144 121 100 E1 D4 C9 BG B5

 ${\displaystyle -1}$ 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 1729