A111676 Array of primes of the type k concatenated with 2n-1 where k < 2n-1. 1---> no prime 13,23 5---> no prime 17,37,47,67 19,29,59,79,89 211,311,811,911 113,313,613,1013,1213 15---> no prime 317,617,... ... Sequence contains the arrays separated by zero for n = 10k +5.

0, 13, 23, 0, 17, 37, 47, 67, 19, 29, 59, 79, 89, 211, 311, 811, 911, 113, 313, 613, 1013, 1213, 0, 317, 617, 1117, 1217, 419, 619, 719, 919, 1019, 1319, 1619, 421, 521, 821, 1021, 1321, 1621, 1721, 223, 523, 823, 1123, 1223, 1423, 1523, 1723, 1823, 0, 127

Offset

1,2

Links

Table of n, a(n) for n=1..52.

Example

For 2n-1 = 9, we have primes 19,29,59,79 and 89. 109 is not included as 10 > 9.

Maple

cat2 := proc(n, m) n*10^(max(1, ilog10(m)+1))+m ; end: A111676 := proc(nrow) local town1, k, a ; town1 := 2*nrow-1 ; a := [] ; for k from 1 to town1-1 do if isprime(cat2(k, town1)) then a := [op(a), cat2(k, town1)] ; fi ; od; if a = [] then RETURN([0]) ; else RETURN(a) ; fi ; end: seq(op(A111676(nrow)), nrow=1..16) ; # R. J. Mathar, Aug 20 2007

Crossrefs

Cf. A111677.

Sequence in context: A301962 A298235 A392949 * A372056 A363482 A058030

Adjacent sequences: A111673 A111674 A111675 * A111677 A111678 A111679

Keyword

base,nonn,tabf

Author

Amarnath Murthy, Aug 16 2005

Extensions

More terms from R. J. Mathar, Aug 20 2007

Status

approved