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A333531 Make a list of triples [n,k,m] with n>=1, k>=1, and T_n+T_k = T_m as in A309507, arranged in lexicographic order; sequence gives values of m. 3
3, 6, 10, 6, 8, 15, 8, 11, 21, 28, 13, 36, 10, 11, 16, 23, 45, 13, 28, 55, 18, 23, 66, 21, 27, 78, 16, 46, 91, 15, 18, 20, 23, 36, 53, 105, 26, 41, 120, 136, 21, 28, 52, 77, 153, 23, 31, 58, 86, 171, 40, 49, 190, 21, 23, 33, 44, 54, 71, 210, 23, 26, 36, 41, 78, 116, 231, 28, 253 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..69.

J. S. Myers, R. Schroeppel, S. R. Shannon, N. J. A. Sloane, and P. Zimmermann, Three Cousins of Recaman's Sequence, arXiv:2004:14000, April 2020

EXAMPLE

The first few triples are:

2, 2, 3

3, 5, 6

4, 9, 10

5, 3, 6

5, 6, 8

5, 14, 15

6, 5, 8

6, 9, 11

6, 20, 21

7, 27, 28

8, 10, 13

8, 35, 36

9, 4, 10

9, 6, 11

9, 13, 16

9, 21, 23

9, 44, 45

10, 8, 13

10, 26, 28

10, 54, 55

11, 14, 18

11, 20, 23

11, 65, 66

12, 17, 21

12, 24, 27

12, 77, 78

...

MAPLE

# This program produces the triples for each value of n, but then they need to be sorted on k:

with(numtheory):

A:=[]; M:=100;

for n from 1 to M do

TT:=n*(n+1);

dlis:=divisors(TT);

for d in dlis do

if (d mod 2) = 1 then e := TT/d;

mi:=min(d, e); ma:=max(d, e);

k:=(ma-mi-1)/2;

m:=(ma+mi-1)/2;

# skip if k=0

if k>0 then

lprint(n, k, m);

fi;

fi;

od:

od:

CROSSREFS

Cf. A000217, A309507, A333529, A333530.

If we only take triples [n,k,m] with n <= k <= m, the values of k and m are A198455 and A198456 respectively.

Sequence in context: A329153 A232175 A065234 * A082184 A080817 A139762

Adjacent sequences:  A333528 A333529 A333530 * A333532 A333533 A333534

KEYWORD

nonn

AUTHOR

N. J. A. Sloane, Apr 01 2020

STATUS

approved

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Last modified August 8 19:29 EDT 2020. Contains 336298 sequences. (Running on oeis4.)