The On-Line Encyclopedia of Integer Sequences (OEIS)

Revision History for A077718

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A077718

Primes which can be expressed as sum of distinct powers of 4.
(history; published version)

#17 by Alois P. Heinz at Thu Sep 06 19:28:23 EDT 2018

STATUS

proposed

approved

#16 by Robert Israel at Thu Sep 06 19:14:18 EDT 2018

STATUS

editing

proposed

#15 by Robert Israel at Thu Sep 06 19:13:49 EDT 2018

LINKS

Robert Israel, <a href="/A077718/b077718.txt">Table of n, a(n) for n = 1..10000</a>

MAPLE

f:= proc(n) local L, x;

L:= convert(n, base, 2);

x:= 1+add(L[i]*4^i, i=1..nops(L));

if isprime(x) then x fi

end proc:

map(f, [$1..1000]); # Robert Israel, Sep 06 2018

STATUS

approved

editing

#14 by M. F. Hasler at Sun Jan 12 15:04:32 EST 2014

STATUS

editing

approved

#13 by M. F. Hasler at Sun Jan 12 15:03:42 EST 2014

COMMENTS

As a subsequence of primes in A000695, these would could be called Moser-de Bruijn primes. See also A235461 for those numbers terms whose base 4 representation also represents a prime in base 2. - M. F. Hasler, Jan 11 2014

PROG

(PARI) for(i=1, 999, isprime(b=vector(#b=binary(i), j, 4^(#b-j))*b~)&&print1(b", ")) \\ - M. F. Hasler, Jan 12 2014

#12 by M. F. Hasler at Sat Jan 11 15:43:46 EST 2014

COMMENTS

As a subsequence of primes in A000695, these would be called Moser-de Bruijn primes. See also A235461 for those numbers whose base 4 representation also represents a prime in base 2. - M. F. Hasler, Jan 11 2014

STATUS

approved

editing

#11 by N. J. A. Sloane at Thu Dec 05 19:55:55 EST 2013

AUTHOR

_Amarnath Murthy (amarnath_murthy(AT)yahoo.com), _, Nov 19 2002

Discussion

Thu Dec 05

19:55

OEIS Server: https://oeis.org/edit/global/2075

#10 by Bruno Berselli at Wed May 22 11:07:22 EDT 2013

STATUS

proposed

approved

#9 by Jayanta Basu at Wed May 22 10:20:42 EDT 2013

STATUS

editing

proposed

#8 by Jayanta Basu at Wed May 22 10:20:28 EDT 2013

MATHEMATICA

Select[Prime[Range[6650]], Max[Union[IntegerDigits[#, 4]]]<=1&] (* Jayanta Basu, May 22 2013 *)

STATUS

proposed

editing