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A065604 a(n) = smallest k satisfying the equation phi(k) = phi(k-1) + phi(k-2) and having just n prime factors. 0
3, 1037, 619697, 218688017, 32617225577 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
LINKS
EXAMPLE
a(1) = 3 which is prime and is the first term in A065557, a(2) = 1037 = 17*61 which is the first term in A065572, a(3) = 619697=13*73*653
MATHEMATICA
a = Table[0, {4}]; x = y = 1; Do[ z = EulerPhi[n]; If[z == x + y, If[l = Length[ FactorInteger[ n]]; a[[l]] == 0, a[[l]] = n; Print[n]]]; x = y; y = z, {n, 3, 10^7 } ]; a
CROSSREFS
Cf. A065557 and A065572.
Sequence in context: A152505 A139301 A004803 * A062612 A096082 A274994
KEYWORD
hard,nonn
AUTHOR
Robert G. Wilson v, Dec 01 2001
EXTENSIONS
a(5) from Donovan Johnson, Feb 05 2010
STATUS
approved

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Last modified June 27 20:20 EDT 2024. Contains 373753 sequences. (Running on oeis4.)