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A345348 Triangular numbers that in base 2 have the same number of 0's and 1's. 1
10, 153, 210, 595, 666, 820, 2278, 2701, 9045, 9870, 10585, 11476, 12403, 13366, 13861, 14365, 34191, 34716, 35245, 36046, 37675, 37950, 39340, 39621, 40470, 41905, 42195, 42778, 43365, 44551, 45150, 45451, 46665, 48516, 49455, 50086, 50403, 51681, 52003, 52326 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Charles R Greathouse IV, Table of n, a(n) for n = 1..10000

EXAMPLE

Triangular number 153 = '10011001' in binary, the number of 1's equals the number of 0's, so 153 is a term.

MATHEMATICA

Select[Table[n*(n + 1)/2, {n, 0, 330}], Equal @@ DigitCount[#, 2] &] (* Amiram Eldar, Jun 15 2021 *)

PROG

(PARI) isA031443(n)=2*hammingweight(n)==exponent(n)+1

list(lim)=my(v=List(), n=4, t); while((t=n*n++/2)<=lim, if(isA031443(t), listput(v, t))); Vec(v) \\ Charles R Greathouse IV, Jun 21 2021

(Python)

A345348_list = [n for n in (m*(m+1)//2 for m in range(10**6)) if len(bin(n))-2 == 2*bin(n).count('1')] # Chai Wah Wu, Jun 21 2021

CROSSREFS

Intersection of A000217 and A031443.

Cf. A164343.

Sequence in context: A251730 A222487 A307352 * A349490 A269608 A240196

Adjacent sequences:  A345345 A345346 A345347 * A345349 A345350 A345351

KEYWORD

nonn,base

AUTHOR

Ctibor O. Zizka, Jun 15 2021

EXTENSIONS

More terms from Jinyuan Wang, Jun 15 2021

STATUS

approved

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Last modified January 24 08:31 EST 2022. Contains 350534 sequences. (Running on oeis4.)