A257892 Numbers n with property that A062234(n) = A062234(n+1) = A062234(n+2) = A062234(n+3).
332, 878, 1999, 3949, 4524, 5953, 6576, 8676, 10068, 11840, 17107, 17208, 19034, 19525, 46771, 46828, 52767, 54567, 54927, 56879, 58695, 61748, 65926, 77168, 77676, 79722, 92775, 92823, 96099, 101607, 111007, 136141, 160095, 160418, 173404
Offset: 1
Keywords
Examples
a(1) = A258437(A258432(4)) = 332. - _Reinhard Zumkeller_, May 31 2015
Links
- Reinhard Zumkeller, Table of n, a(n) for n = 1..110
Crossrefs
Programs
-
Haskell
a257892 n = a257892_list !! (n-1) a257892_list = map a258432 $ filter ((== 4) . a258383) [1..] -- Reinhard Zumkeller, May 31 2015
-
PARI
d(k) = 2*prime(k)-prime(k+1); isok(n) = (d(n) == d(n+1)) && (d(n+1) == d(n+2)) && (d(n+2) == d(n+3)); \\ Michel Marcus, May 29 2015
-
Perl
use Math::Prime::Util::PrimeArray; tie my @prime,"Math::Prime::Util::PrimeArray"; sub d { 2*$prime[$[0]-1] - $prime[$[0]] } for (1..1e6) { my $dk=d($); say if d($+1)==$dk && d($+2)==$dk && d($+3)==$dk } # Dana Jacobsen, May 31 2015 -
Perl
use ntheory ":all"; { my @prime; sub d { 2*$prime[$[0]-1] - $prime[$[0]] } sub list { my $n=shift; @prime=@{primes(nth_prime($n+5))}; my @d=map{d($)}1..4; my @list; for (1..$n) { push @list,$ if $d[0]==$d[1] && $d[0]==$d[2] && $d[0]==$d[3]; @d=(@d[1..3],d($+4)) } @list; } } say join ", ",list(1e6); # _Dana Jacobsen, May 31 2015
Comments