login
A341706
Row 2 of semigroup multiplication table shown in A341317 and A341318.
3
0, 2, 7, 8, 16, 17, 18, 29, 30, 31, 32, 46, 47, 48, 49, 50, 67, 68, 69, 70, 71, 72, 92, 93, 94, 95, 96, 97, 98, 121, 122, 123, 124, 125, 126, 127, 128, 154, 155, 156, 157, 158, 159, 160, 161, 162, 191, 192, 193, 194, 195, 196, 197, 198, 199, 200, 232, 233, 234
OFFSET
0,2
LINKS
MAPLE
t:= n-> n*(n-1)/2:
f:= n-> ceil((sqrt(1+8*n)-1)/2):
g:= n-> (x-> [x, n-t(x)][])(f(n)):
a:= n-> (h-> t(h[1]*h[3])+h[2]*h[4])(map(g, [n, 2])):
seq(a(n), n=0..60); # Alois P. Heinz, Feb 17 2021
CROSSREFS
Sequence in context: A080572 A263602 A162664 * A032689 A331489 A300476
KEYWORD
nonn
AUTHOR
N. J. A. Sloane, Feb 17 2021
EXTENSIONS
More terms from Alois P. Heinz, Feb 17 2021
STATUS
approved