A191859 - OEIS

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A191859

The primes created by concatenation of anti-divisors in A191647.

2, 3, 23, 347, 349, 311, 391627, 3471331, 384067, 2310175897, 239111323273399, 23167, 3784097136227, 235983149249, 3428116271, 37111677121283, 23293, 3471949133311, 231314228398154359, 378112153101159371, 2379127163381

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,1

COMMENTS

a(n) is the concatenation of the anti-divisors of A191647(n).

LINKS

Klaus Brockhaus, Table of n, a(n) for n = 1..1000

EXAMPLE

A191647(6) = 16, the anti-divisors of 16 are 3, 11. Hence a(6) = 311.

A191647(8) = 46, the anti-divisors of 46 are 3, 4, 7, 13, 31. Hence a(8) = 3471331.

PROG

(Magma) Antidivisors:=func< n | [ d: d in [2..n-1] | n mod d ne 0 and ( (IsEven(d) and 2*n mod d eq 0) or (IsOdd(d) and ((2*n-1) mod d eq 0 or (2*n+1) mod d eq 0)) ) ] >; CAD:=function(n); A:=Antidivisors(n); S:=[]; for k in [1..#A] do S:= Intseq(A[k]) cat S; end for; p:=Seqint(S); return p; end function; A191859List:=func< m | [ p: n in [1..m] | IsPrime(p) where p is CAD(n) ] >; A191859List(600);

CROSSREFS

Cf. A191647, A066272, A130846, A120712.

Sequence in context: A235934 A064888 A104458 * A289550 A154553 A160341

Adjacent sequences: A191856 A191857 A191858 * A191860 A191861 A191862

KEYWORD

nonn,base

AUTHOR

Klaus Brockhaus, Jun 18 2011

STATUS

approved