1,5
When viewed as an irregular table there are A000041 entries per row wich sum to 1 2 6 24 120 720 ...
a(n) = A117506(n)*A117506(n)
Row five of A117506 is 1 4 5 6 5 4 1 so row five of the present triangle is 1 16 25 36 25 16 1
Cf. A000041 A000085 A000142 A007318 A008459 A059797 A117506.
Sequence in context: A100754 A055107 A128137 this_sequence A114188 A110511 A082950
Adjacent sequences: A136097 A136098 A136099 this_sequence A136101 A136102 A136103
nonn,tabf
Alford Arnold (Alford1940(AT)aol.com), Dec 27 2007
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