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A045800
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0-ish numbers (end in 01, 07, 43, 49).
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10
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1, 7, 43, 49, 101, 107, 143, 149, 201, 207, 243, 249, 301, 307, 343, 349, 401, 407, 443, 449, 501, 507, 543, 549, 601, 607, 643, 649, 701, 707, 743, 749, 801, 807, 843, 849, 901, 907, 943, 949, 1001, 1007, 1043, 1049, 1101, 1107, 1143, 1149, 1201, 1207
(list;
graph;
refs;
listen;
history;
text;
internal format)
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OFFSET
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1,2
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LINKS
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FORMULA
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G.f.: x*(1+6*x+36*x^2+6*x^3+51*x^4)/(1-x-x^4+x^5). - Colin Barker, Jan 23 2012
a(n) = (50*n-8*i^(n*(n+1))-19*(-1)^n-75)/2, where i=sqrt(-1). - Bruno Berselli, Feb 22 2012
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MATHEMATICA
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LinearRecurrence[{1, 0, 0, 1, -1}, {1, 7, 43, 49, 101}, 60] (* Harvey P. Dale, Jul 26 2015 *)
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PROG
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(Haskell)
import Data.List (findIndices)
a045800 n = a045800_list !! (n-1)
a045800_list = findIndices (`elem` [1, 7, 43, 49]) $ cycle [0..99]
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CROSSREFS
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KEYWORD
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nonn,base,easy
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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