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

1,1

Comments

a(n) = A258432(m), where m such that A258383(m) = 4. - Reinhard Zumkeller, May 31 2015

Links

Reinhard Zumkeller, Table of n, a(n) for n = 1..110

Example

a(1) = A258437(A258432(4)) = 332. - Reinhard Zumkeller, May 31 2015

Prog

(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
(Haskell)
a257892 n = a257892_list !! (n-1)
a257892_list = map a258432 $ filter ((== 4) . a258383) [1..]
-- Reinhard Zumkeller, May 31 2015

Crossrefs

Subsequence of A257762 and A062234.

Cf. A258383, A258432, A258437, A258469, A258449, A257892, A257951.

Sequence in context: A376734 A250758 A114084 * A235020 A111690 A095199

Adjacent sequences: A257889 A257890 A257891 * A257893 A257894 A257895

Keyword

nonn

Author

Zak Seidov, May 14 2015

Status

approved