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A212192 Triangular numbers that are the sum of exactly three distinct powers of 2. 3
21, 28, 276, 1540 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
COMMENTS
Triangular numbers with exactly three ones in their binary representation: A000120(a(n)) = 3; triangular numbers in A014311; no more terms less than A014311(1000000) = 6129982174881536975083663305496791903885182827960991744.
LINKS
MATHEMATICA
Select[Accumulate[Range[60]], Total[IntegerDigits[#, 2]]==3&] (* Harvey P. Dale, Mar 11 2023 *)
PROG
(Haskell)
a212192 n = a212192_list !! (n-1)
a212192_list = filter ((== 1) . a010054) a014311_list
CROSSREFS
Sequence in context: A162692 A048067 A344603 * A166647 A119107 A004196
KEYWORD
nonn
AUTHOR
Reinhard Zumkeller, May 03 2012
STATUS
approved

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Last modified March 29 02:23 EDT 2024. Contains 371264 sequences. (Running on oeis4.)