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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 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

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

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

Cf. A341317, A341318.

Sequence in context: A080572 A263602 A162664 * A032689 A331489 A300476

Adjacent sequences:  A341703 A341704 A341705 * A341707 A341708 A341709

KEYWORD

nonn

AUTHOR

N. J. A. Sloane, Feb 17 2021

EXTENSIONS

More terms from Alois P. Heinz, Feb 17 2021

STATUS

approved

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Last modified June 24 10:36 EDT 2021. Contains 345416 sequences. (Running on oeis4.)