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A258258 Least number k having exactly n representations as a sum of the minimal number of triangular numbers, A000217. 2
1, 16, 40, 75, 52, 82, 166, 178, 147, 217, 334, 247, 481, 634, 457, 516, 921, 646, 1047, 1132, 822, 787, 2110, 1351, 1537, 1542, 1402, 1192, 1666, 1696, 2137, 1759, 1876, 2271, 1792, 2712, 2587, 3216, 3909, 2782, 3007, 2956, 4242, 3397, 3682, 4039, 3607, 3601 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,2
COMMENTS
Fermat's polygonal number theorem states that every positive integer is a sum of at most n n-gonal numbers. The triangular case was proved in 1796 by Gauss (Eureka theorem), stating that every positive integer is the sum of at most three triangular numbers. This sequence is based on this representation as a sum of the minimal number of triangular numbers.
LINKS
EXAMPLE
a(2) = 16 = 1 + 15 = 6 + 10 is the smallest number with two representations.
a(3) = 40 = 1 + 3 + 36 = 6 + 6 + 28 = 10 + 15 + 15 is the smallest number with three representations.
a(4) = 75 = 3 + 6 + 66 = 3 + 36 + 36 = 10 + 10 + 55 = 15 + 15 + 45 is the smallest number with four representations.
CROSSREFS
Sequence in context: A332519 A177723 A174321 * A086046 A184030 A350284
KEYWORD
nonn
AUTHOR
Martin Renner, May 24 2015
STATUS
approved

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Last modified March 28 14:37 EDT 2024. Contains 371254 sequences. (Running on oeis4.)