551

From ProofWiki
Jump to navigation Jump to search

Previous  ... Next

Number

$551$ (five hundred and fifty-one) is:

$19 \times 29$


The $19$th second pentagonal number after $2$, $7$, $15$, $26$, $40$, $57$, $77$, $100$, $126$, $155$, $187$, $222$, $260$, $301$, $345$, $392$, $442$, $495$:
$551 = \dfrac {19 \paren {3 \times 19 + 1} } 2$


The $38$th generalized pentagonal number after $1$, $2$, $5$, $7$, $12$, $15$, $\ldots$, $392$, $425$, $442$, $477$, $495$, $532$:
$551 = \dfrac {19 \paren {3 \times 19 + 1} } 2$


Also see