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A038494
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Images of hexamorphic numbers: suppose k-th hexagonal number H(k) (A000384) ends in k; sequence gives positive values of H(k).
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1
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1, 45, 66, 1225, 1326, 4950, 5151, 11175, 11476, 31125, 282376, 499500, 501501, 780625, 1533876, 38294376, 49995000, 50015001, 63275625, 175809376, 3300740625, 4999950000, 5000150001, 7050959376, 16425690625, 23926109376
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OFFSET
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1,2
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REFERENCES
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D. Wells, The Penguin Dictionary of Curious and Interesting Numbers, Penguin Book, p. 104.
C. Pickover, Computers and Imagination, 1991.
C. A. Pickover, Hexamorphic numbers, in Hexagonal cats Ch. 63 in Wonders of Numbers: Adventures in Mathematics, Mind, and Meaning, Oxford, England: Oxford University Press, pp. 154, 2001.
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LINKS
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EXAMPLE
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45 is included because it is the 5th hexagonal number and it ends in 5.
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MATHEMATICA
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Select[Array[{PolygonalNumber[6, #], #} &, 10^6], FromDigits[Take[IntegerDigits[#], -IntegerLength@ #2]] == #2 & @@ # &][[All, 1]] (* Michael De Vlieger, Jun 30 2018 *)
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PROG
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(PARI) lista(nn) = {for (n=1, nn, m = n*(2*n-1); if ((m - n) % 10^#Str(n) == 0, print1(m, ", ")); ); } \\ Michel Marcus, Sep 25 2015
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CROSSREFS
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KEYWORD
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nonn,base
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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