805
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Number
$805$ (eight hundred and five) is:
- $5 \times 7 \times 23$
- The $23$rd second pentagonal number after $2$, $7$, $15$, $26$, $\ldots$, $222$, $260$, $301$, $345$, $392$, $442$, $495$, $551$, $610$, $672$, $737$:
- $805 = \dfrac {23 \paren {3 \times 23 + 1} } 2$
- The $46$th generalized pentagonal number after $1$, $2$, $5$, $7$, $12$, $15$, $\ldots$, $392$, $425$, $442$, $477$, $495$, $532$, $551$, $590$, $610$, $651$, $672$, $715$, $737$, $782$:
- $805 = \dfrac {23 \paren {3 \times 23 + 1} } 2$