

A108156


Numbers n such that a(n) is prime, where a(n) = a(n1) + a(n2), a(1) = 3794765361567513, a(2) = 20615674205555510.


0



138, 163, 190, 523, 1855, 3228, 3579, 6468, 7170, 10230, 12783, 17259, 60139, 91315, 97923, 101823, 156075
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OFFSET

1,1


COMMENTS

In his biography of Paul Erdős, Hoffman cited Wilf's Fibonaccilike primefree sequence (A083216). But, as Weisstein points out, Hoffman inadvertently switched the two initial terms, resulting in a sequence that appears primefree for the first 137 terms. Term 138 is 439351292910452432574786963588089477522344721, which is prime. The first Mathematica program below comes from Weisstein's Mathematica notebook.


REFERENCES

Paul Hoffman. The Man Who Loved Only Numbers: The Story of Paul Erdős and the Search for Mathematical Truth. New York: Hyperion, 1998.


LINKS



MATHEMATICA

a[1] := 3794765361567513; a[2] := 20615674205555510; a[n_] := a[n] = a[n  2] + a[n  1]; Flatten[Position[Table[a[n], {n, 10^4}], _?PrimeQ]] (* Eric W. Weisstein *)
Flatten[Position[LinearRecurrence[{1, 1}, {3794765361567513, 20615674205555510}, 160000], _?PrimeQ]] (* Harvey P. Dale, Nov 29 2011 *)


CROSSREFS



KEYWORD

nonn


AUTHOR



EXTENSIONS



STATUS

approved



