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A101180 Numbers n such that 19*n^2 + 19*n + 1 is a square. +0
2
0, 8, 671, 15639, 42159, 981911, 77624048, 1807894920, 4873553880, 113507005568, 8973184757831, 208989037004319, 563373081435879 (list; graph; listen)
OFFSET

1,2

COMMENT

Define a(1)=0, a(2)=8, a(3)=671, a(4)=15639, a(5)=42159, a(6)=981911, the first 6 terms found for the sequence then a(7)=57799*(2*a(3)+1)-a(2)-1, a(8)=57799*(2*a(4)+1)-a(1)-1 for n>8 a(n)=57799*(2*a(n-4)+1)-a(n-8)-1 remark:57799 = 38*39*39+1 =2*19*(39^2)+1

CROSSREFS

Cf. A105839.

Adjacent sequences: A101177 A101178 A101179 this_sequence A101181 A101182 A101183

Sequence in context: A129927 A015106 A099126 this_sequence A128875 A037076 A116245

KEYWORD

nonn,more

AUTHOR

Pierre CAMI (pierrecami(AT)tele2.fr), Apr 06 2005, Apr 22 2005

EXTENSIONS

Edited by N. J. A. Sloane (njas(AT)research.att.com), Aug 29 2008 at the suggestion of R. J. Mathar

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Last modified November 9 12:23 EST 2009. Contains 166233 sequences.


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