1426

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Number

$1426$ (one thousand, four hundred and twenty-six) is:

$2 \times 23 \times 31$


The $31$st pentagonal number after $1$, $5$, $12$, $22$, $35$, $\ldots$, $925$, $1001$, $1080$, $1162$, $1247$, $1335$:
$1426 = \ds \sum_{k \mathop = 1}^{31} \paren {3 k - 2} = \dfrac {31 \paren {3 \times 31 - 1} } 2$


The $61$st generalized pentagonal number after $1$, $2$, $5$, $7$, $12$, $15$, $\ldots$, $925$, $950$, $1001$, $1027$, $1080$, $1107$, $1162$, $1190$, $1247$, $1276$, $1335$, $1365$:
$1426 = \ds \sum_{k \mathop = 1}^{31} \paren {3 k - 2} = \dfrac {31 \paren {3 \times 31 - 1} } 2$


Also see