The On-Line Encyclopedia of Integer Sequences (OEIS)

Revision History for A181675 (Bold, blue-underlined text is an addition; faded, red-underlined text is a ~~deletion~~.)
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A181675

V(n,n^2), where V is the number of integer points in an n-dimensional sphere of Lee-radius n^2 centered at the origin.
(history; published version)

#12 by Vaclav Kotesovec at Sat Feb 13 04:31:32 EST 2021

STATUS

editing

approved

#11 by Vaclav Kotesovec at Sat Feb 13 04:31:16 EST 2021

FORMULA

a(n) ~ exp(n-2) * (2*n)^(n - 3/2) / sqrt(Pi). - Vaclav Kotesovec, Feb 13 2021

STATUS

approved

editing

#10 by Peter Luschny at Sat Jul 06 04:13:04 EDT 2019

STATUS

reviewed

approved

#9 by Joerg Arndt at Sat Jul 06 01:48:49 EDT 2019

STATUS

proposed

reviewed

#8 by Michel Marcus at Fri Jul 05 23:59:05 EDT 2019

STATUS

editing

proposed

#7 by Michel Marcus at Fri Jul 05 23:58:35 EDT 2019

REFERENCES

Solomon W. Golomb and Lloyd R. Welch, "Perfect Codes in the Lee Metric and the Packing of Polyominoes", SIAM Journal on Applied Mathematics Vol. 18, No. 2 (Mar. 1970), pp. 302-317.

Milan Janjić, <a href="https://arxiv.org/abs/1905.04465">On Restricted Ternary Words and Insets</a>, arXiv:1905.04465 [math.CO], 2019.

LINKS

Solomon W. Golomb and Lloyd R. Welch, <a href="https://www.jstor.org/stable/2099465">Perfect Codes in the Lee Metric and the Packing of Polyominoes</a>, SIAM Journal on Applied Mathematics Vol. 18, No. 2 (Mar. 1970), pp. 302-317.

Milan Janjić, <a href="https://arxiv.org/abs/1905.04465">On Restricted Ternary Words and Insets</a>, arXiv:1905.04465 [math.CO], 2019.

FORMULA

V(n,d) = sum_Sum_{j=0..min(n,d)} 2^j * binomial(n,j)*binomial(d,j).

STATUS

proposed

editing

Discussion

Fri Jul 05

23:59

Michel Marcus: because of "in an n-dimensional sphere" ?

#6 by Michael De Vlieger at Fri Jul 05 18:22:06 EDT 2019

STATUS

editing

proposed

#5 by Michael De Vlieger at Fri Jul 05 18:21:06 EDT 2019

REFERENCES

Milan Janjić, <a href="https://arxiv.org/abs/1905.04465">On Restricted Ternary Words and Insets</a>, arXiv:1905.04465 [math.CO], 2019.

MATHEMATICA

Array[Sum[2^j * Binomial[n, #1, j]* Binomial[d, #2, j], {j, 0 , Min[n, d#1, #2]}] & @@ {#, #^2} &, 13] (* _Michael De Vlieger_, Jul 05 2019 *)

STATUS

approved

editing

Discussion

Fri Jul 05

18:22

Michael De Vlieger: Not sure why offset = 2. Replaced faulty Mathematica code with a similar script that produces the sequence.

#4 by Alois P. Heinz at Mon Feb 16 20:03:01 EST 2015

STATUS

proposed

approved

#3 by Jon E. Schoenfield at Mon Feb 16 20:01:15 EST 2015

STATUS

editing

proposed