228 (number)

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228 (two hundred [and] twenty-eight) is the natural number following 227 and preceding 229.

In mathematics

← 227 228 229 →
Cardinal two hundred twenty-eight
Ordinal 228th
(two hundred twenty-eighth)
Factorization 22 × 3 × 19
Prime no
Greek numeral ΣΚΗ´
Roman numeral CCXXVIII, ccxxviii
Binary 111001002
Ternary 221103
Senary 10206
Octal 3448
Duodecimal 17012
Hexadecimal E416

228 is a refactorable number [1] and a practical number. [2] There are 228 matchings in a ladder graph with five rungs. [3] 228 is the smallest even number n such that the numerator of the nth Bernoulli number is divisible by a nontrivial square number that is relatively prime to n. [4]

The binary form of 228 contains all the two digit binary numbers in sequence from highest to lowest (11 10 01 00).

References

  1. ↑ Sloane, N. J. A. (ed.). "SequenceA033950(Refactorable numbers)". The On-Line Encyclopedia of Integer Sequences . OEIS Foundation.
  2. ↑ Sloane, N. J. A. (ed.). "SequenceA005153(Practical numbers)". The On-Line Encyclopedia of Integer Sequences . OEIS Foundation.
  3. ↑ Sloane, N. J. A. (ed.). "SequenceA030186(a(n) = 3a(n-1) + a(n-2) - a(n-3))". The On-Line Encyclopedia of Integer Sequences . OEIS Foundation.
  4. ↑ Sloane, N. J. A. (ed.). "SequenceA090943(Even numbers n such that N(n) is divisible by a nontrivial square, m^2, say and GCD(n,m)=1, where N(n) is the numerator of the Bernoulli number B(n))". The On-Line Encyclopedia of Integer Sequences . OEIS Foundation.
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