A069619 a(1) = 7; a(2n) = smallest prime that is a right concatenation of a(2n-1) and a number with no insignificant zeros and a(2n+1) = smallest prime ending in ( the least significant digits) a(2n-1). Alternate left and right concatenation yielding primes.

7, 71, 271, 2711, 52711, 5271121, 135271121, 1352711219, 271352711219, 27135271121911, 1227135271121911, 122713527112191161, 20122713527112191161, 20122713527112191161109, 2720122713527112191161109

Offset

1,1

Links

Table of n, a(n) for n=1..15.

Example

a(4) = 2711 staring with a(3) =271 and a(5) = 52711 in a(4) = 2711.

Crossrefs

Cf. A053582, A069605, A069606, A069607, A069608, A069609, A069610, A069611, A069613, A069614, A069615, A069616, A069617, A069618.

Sequence in context: A142928 A201261 A069634 * A137443 A362106 A107601

Adjacent sequences: A069616 A069617 A069618 * A069620 A069621 A069622

Keyword

nonn,base

Author

Amarnath Murthy, Mar 27 2002

Extensions

More terms from Antonio G. Astudillo (afg_astudillo(AT)lycos.com), Mar 30 2003

Status

approved