OFFSET
1,2
EXAMPLE
The permutations of 4 elements and the respective sums are
[ 1 2 3 4 ] 100
[ 1 2 4 3 ] 93
[ 1 3 2 4 ] 95
[ 1 3 4 2 ] 81
[ 1 4 2 3 ] 83
[ 1 4 3 2 ] 76
[ 2 1 3 4 ] 97
[ 2 1 4 3 ] 90
[ 2 3 1 4 ] 87
[ 2 3 4 1 ] 66
[ 2 4 1 3 ] 75
[ 2 4 3 1 ] 61
[ 3 1 2 4 ] 89
[ 3 1 4 2 ] 75 // same as [ 2 4 1 3 ]
[ 3 2 1 4 ] 84
[ 3 2 4 1 ] 63
[ 3 4 1 2 ] 60
[ 3 4 2 1 ] 53
[ 4 1 2 3 ] 74
[ 4 1 3 2 ] 67
[ 4 2 1 3 ] 69
[ 4 2 3 1 ] 55
[ 4 3 1 2 ] 57
[ 4 3 2 1 ] 50
All values except 75 are unique, so a(4) = 4!-1 = 23.
CROSSREFS
KEYWORD
nonn,more
AUTHOR
Joerg Arndt, Apr 22 2011
EXTENSIONS
Corrected terms (error pointed out by Alois P. Heinz), Joerg Arndt, Apr 28 2011.
a(14) from Alois P. Heinz, Apr 28 2011
STATUS
approved