

A135617


a(n) is the initial digit of nth even perfect number.


7



6, 2, 4, 8, 3, 8, 1, 2, 2, 1, 1, 1, 2, 1, 5, 1, 9, 3, 1, 4, 1, 5, 3, 9, 1, 8, 3, 1, 1, 1, 2, 1, 8, 8, 3, 1, 8, 9, 4, 7, 4, 7, 4, 7, 2, 1, 5
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OFFSET

1,1


COMMENTS

a(n) is also the initial digit of nth perfect number A000396(n) if there are no odd perfect numbers.


LINKS

Table of n, a(n) for n=1..47.
Omar E. Pol, Los nĂºmeros perfectos, (in Spanish).


EXAMPLE

a(5) = 3 because the 5th even perfect number is 33550336 and the initial digit of 33550336 is 3.


MATHEMATICA

lst = {* the list of terms in A000043 *}; f[n_] := Block[{pn = (2^n  1) (2^(n  1))}, Quotient[pn, 10^Floor[ Log[10, pn]] ]]; f@# & /@ lst  Robert G. Wilson v, Apr 01 2008


CROSSREFS

Cf. A000030, A000396, A077648, A094540, A133033.
Sequence in context: A020831 A298777 A156590 * A019930 A169843 A123139
Adjacent sequences: A135614 A135615 A135616 * A135618 A135619 A135620


KEYWORD

nonn,base,more


AUTHOR

Omar E. Pol, Mar 01 2008


EXTENSIONS

More terms from Robert G. Wilson v, Apr 01 2008
Definition clarified by Omar E. Pol, Apr 14 2018
a(40)a(47) from Ivan Panchenko, Apr 16 2018


STATUS

approved



