Al Zimmermann has authored 4 sequences.
A355015
The least integer with cost n, using the cost function used in sequence A354914.
Original entry on oeis.org
1, 2, 3, 7, 23, 719, 1169951
Offset: 0
Example: a(4) = 23 because 23 can be reached by the path 1, 2, 3, 4, 5, 20, 23, which has 4 addition steps, and one can check that each smaller number has cost at most 3.
A115866
a(n) = g(n,n,n) where g(a, b, c) is defined as follows: if a = 0 or b = 0 or c = 0 then return 1 otherwise return g(a, b, c-1) + g(a, b-1, c) + g(a-1, b, c) + g(a, b-1, c-1) + g(a-1, b, c-1) + g(a-1, b-1, c) + g(a-1, b-1, c-1).
Original entry on oeis.org
1, 7, 157, 5419, 220561, 9763807, 454635973, 21894817147, 1080094827649, 54250971690007, 2763339510402637, 142338478909290187, 7399210542653679985, 387578046480606144079, 20433042381373273363477, 1083193405190852829195259, 57697563083258107660231681
Offset: 0
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g():= seq(convert(n, base, 2)[1..3], n=9..15):
b:= proc(l) option remember;
`if`(l[1]=0, 1, add(b(sort(l-h)), h=g()))
end:
a:= n-> b([n$3]):
seq(a(n), n=0..25); # Alois P. Heinz, Oct 14 2015
-
g[] = Table[Reverse[IntegerDigits[n, 2]][[;; 3]], {n, 2^3 + 1, 2^4 - 1}];
b[l_] := b[l] = If[l[[1]] == 0, 1, Sum[b[Sort[l - h]], {h, g[]}]];
a[n_] := b[Table[n, {3}]];
a /@ Range[0, 25] (* Jean-François Alcover, Apr 25 2020, after Alois P. Heinz *)
A068940
Maximum number of chess queens that can be placed on a 3-dimensional chessboard of order n so that no two queens attack each other.
Original entry on oeis.org
1, 1, 4, 7, 13, 21, 32, 48, 67, 91, 121, 133, 169
Offset: 1
A068941
Maximum number of chess queens that can be placed on a 4-dimensional chessboard of order n so that no two attack each other.
Original entry on oeis.org
1, 1, 6, 16, 38, 80, 145
Offset: 1
a(5) from Alexis Langlois-Rémillard, Christoph Müßig and Érika Roldán added by
Christoph Muessig, Nov 11 2022
a(6)-a(7) from Alexis Langlois-Rémillard, Christoph Müßig and Érika Roldán added by
Christoph Muessig, Apr 02 2023
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