A189043 For all permutations of [1..n]: number of distinct values taken by sum(k=1..n, k^2 * pi(k) ).

1, 2, 6, 23, 89, 232, 437, 747, 1191, 1806, 2631, 3709, 5087, 6816

Offset

1,2

Links

Table of n, a(n) for n=1..14.

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

Cf. A126972 (sum k*pi(k)).

Sequence in context: A150275 A335537 A150276 * A228392 A190910 A150277

Adjacent sequences: A189040 A189041 A189042 * A189044 A189045 A189046

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