# Calculate 1**2 + 2**2 + 3**2 + ...

seq -s^2+ 11 |rev| cut -d'+' -f2- | rev | bc
I can't put the last ^2 with seq, so I reverse it to delete the last +N. So for doing sum(N^2) you have to do sum((N+1)^2). Must be a better way.
Sample Output
`385`

-2
2011-02-10 08:41:14

## 2 Alternatives + Submit Alt

• 2
seq -f"%g^2" -s "+" 10 | bc
· 2011-02-12 23:35:57
• Simplified the series to a polynomial and send it to bc

0
N=10; echo "(\$N*(\$N+1)*(2*\$N+1))/6" | bc
· 2011-02-15 20:02:57

### What Others Think

I like your use of the seq separator, but this time it doesn't quite work. You can replace rev, cut, rev with sed: `seq -s^2+ 11 | sed 's/\$/^2/' | bc` or go back to sed and paste `seq 11 | sed 's/\$/^2/' | paste -sd+ | bc` These also mean that "seq N" gives the sum to N^2.
flatcap · 625 weeks and 6 days ago
With some math `python -c 'n=10;print n*(n+1)*(2*n+1)/6'`
sarcilav · 625 weeks and 6 days ago
The same idea, but with echo and bc `echo 'n=10;n*(n+1)*(2*n+1)/6'|bc`
sarcilav · 625 weeks and 6 days ago
Thanks flatcap! I shoud have think o adding a trailing ^2 :S.
rubenmoran · 625 weeks and 6 days ago

### What do you think?

Any thoughts on this command? Does it work on your machine? Can you do the same thing with only 14 characters?

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