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A214420
Numbers not representable as the sum of three 11-gonal numbers.
2
4, 5, 6, 7, 8, 9, 10, 14, 15, 16, 17, 18, 19, 20, 21, 24, 25, 26, 27, 28, 29, 34, 35, 36, 37, 38, 39, 40, 43, 44, 45, 46, 47, 48, 49, 50, 51, 53, 54, 55, 56, 57, 62, 63, 64, 65, 66, 67, 68, 72, 73, 74, 75, 76, 77, 78, 79, 81, 82, 83, 84, 85, 86, 87, 91, 92
OFFSET
1,1
COMMENTS
It is conjectured that 12453 positive numbers are not the sum of three 11-gonal numbers.
REFERENCES
R. K. Guy, Unsolved Problems in Number Theory, D3.
LINKS
MATHEMATICA
nn = 900; hen = Table[n*(9*n-7)/2, {n, 0, nn}]; t = Table[0, {hen[[-1]]}]; Do[n = hen[[i]] + hen[[j]] + hen[[k]]; If[n <= hen[[-1]], t[[n]] = 1], {i, nn}, {j, i, nn}, {k, j, nn}]; Flatten[Position[t, 0]]
CROSSREFS
Cf. A051682 (11-gonal numbers).
Sequence in context: A227763 A039091 A189817 * A173888 A341051 A120181
KEYWORD
nonn,fini
AUTHOR
T. D. Noe, Jul 17 2012
STATUS
approved