A341706 Row 2 of semigroup multiplication table shown in A341317 and A341318.

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

Author

N. J. A. Sloane, Feb 17 2021

Keywords

• nonn

Links

• Alois P. Heinz, Table of n, a(n) for n = 0..10000

Crossrefs

Cf. A341317, A341318.

Programs

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

Extensions

More terms from Alois P. Heinz, Feb 17 2021