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Indices of Fibonacci numbers (A000045) that are triangular numbers (A000217).
0

%I #34 Feb 03 2018 13:12:46

%S 0,1,2,4,8,10

%N Indices of Fibonacci numbers (A000045) that are triangular numbers (A000217).

%C The sequence of Fibonacci numbers that are also triangular numbers begins: 0, 1, 1, 3, 21, 55. That is, 0 and 1 followed by A039595.

%e Fibonacci(10)=55 is a triangular number, therefore 10 is in the sequence.

%Y Cf. A000045, A000217, A039595, A162394, A121343, A121874.

%K nonn,fini,full

%O 1,3

%A _Alex Ratushnyak_, Jan 24 2018