A115741 Semiprimes (A001358) whose digit reversal is a triangular number.

6, 10, 51, 55, 82, 87, 309, 501, 649, 694, 1198, 1207, 1473, 1765, 1803, 1837, 1959, 1981, 3043, 3057, 3561, 3574, 5158, 5221, 5721, 6139, 6193, 6267, 6535, 6711, 6814, 6843, 10473, 10497, 11553, 12477, 12693, 13123, 13701, 13951, 14169

Offset

1,1

Links

Table of n, a(n) for n=1..41.

Example

51=3*17 is semiprime and 15=T(5).

Crossrefs

Cf. A001358, A115742.

Sequence in context: A346501 A115917 A275004 * A177168 A136843 A219776

Adjacent sequences: A115738 A115739 A115740 * A115742 A115743 A115744

Keyword

nonn,base

Author

Giovanni Resta, Jan 31 2006

Status

approved