

A277603


Exceptional Bobo numbers: terms of A242679 that satisfy frac[e*A242679(n)]<(e1)/2.


3



36, 9045, 5195512, 5311399545, 8488859795196, 25466579385587, 19542965851120621, 58628897553361862, 61250772004870841520, 183752316014612524559, 250769086731739376780337, 752307260195218130341010, 1299515735021702625544976020, 3898547205065107876634928059
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OFFSET

1,1


COMMENTS

The exceptional Bobo numbers (EBNs) are very rare relative to the Bobo numbers (A242679).
Exceptional Bobo numbers come in two varieties. Type1 EBNs are given by the recurrence E(0)=1,E(1)=1,E(k)=(2*k1)*(2*E(k1)1)+E(k2) for k=3,5,7,... These are derived from the denominators of the oddindexed convergents of the continued fraction expansion of (e1)/2 = [0;1,6,10,14,18,...]. The Type2 EBNs are derived from the Type1 EBNs. They have the form n*m(m1)/2 where n is a Type1 EBN and m>=3 is an odd integer. However, not every number of this form is an EBN.


REFERENCES

S. J. Kifowit, A. Mitchell, and S. Zandi, Exceptional Bobo Numbers, in preparation 2016


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CROSSREFS



KEYWORD

nonn


AUTHOR



STATUS

approved



