341

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Number

$341$ (three hundred and forty-one) is:

$11 \times 31$

The $1$st Poulet number:

$2^{341} \equiv 2 \pmod {341}$: $341 = 11 \times 31$

The $4$th Fermat pseudoprime to base $4$ after $15$, $85$, $91$:

$4^{341} \equiv 4 \pmod {341}$

The $11$th octagonal number, after $1$, $8$, $21$, $40$, $65$, $96$, $133$, $176$, $225$, $280$:

$341 = 1 + 7 + 13 + 19 + 25 + 31 + 37 + 43 + 49 + 55 = \ds \sum_{k \mathop = 1}^n \paren {6 k - 5} = 11 \paren {3 \times 11 - 2}$

Also see

• Previous  ... Next: Fermat Pseudoprime to Base 4
• Previous  ... Next: Octagonal Number

• Next: Poulet Number

Sources

• 1986: David Wells: Curious and Interesting Numbers ... (previous) ... (next): $341$
• 1997: David Wells: Curious and Interesting Numbers (2nd ed.) ... (previous) ... (next): $341$