A255724 List of numbers such that no number, nor its reverse, is in the concatenation of all previous terms.

1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 13, 14, 15, 16, 17, 18, 20, 22, 24, 25, 26, 27, 29, 30, 33, 35, 36, 37, 38, 40, 44, 46, 47, 49, 50, 55, 57, 58, 60, 66, 69, 70, 77, 80, 88, 90, 99, 100, 102, 103, 104, 105, 106, 107, 108, 109, 112, 114, 115, 116, 117, 118, 122

Offset

1,2

Links

Table of n, a(n) for n=1..64.

Example

After listing 1..11, 12 is not listed as "12" is found in the concatenated earlier terms. After continuing with 13..18, 19 is not listed as "91" is likewise found.

Prog

(Perl) $s=""; $_=0; do{$_++; if(index($s, $_)<0 && index($s, reverse)<0){print("$_ "); $s.=$_}}while(1);
(PARI) lista(nn) = my(d, v=[]); for(n=1, nn, for(i=0, #v-#d=digits(n), (v[i+1..i+#d]==d || v[i+1..i+#d]==Vecrev(d)) && next(2)); print1(n, ", "); v=concat(v, d)) \\ Jinyuan Wang, Aug 23 2021

Crossrefs

Cf. A048991.

Sequence in context: A343268 A107909 A357758 * A285100 A368007 A360553

Adjacent sequences: A255721 A255722 A255723 * A255725 A255726 A255727

Keyword

nonn,base,easy

Author

Phil Carmody, Mar 19 2015

Extensions

More terms from Jinyuan Wang, Aug 23 2021

Status

approved