A069615 a(1) = 3; a(2n) = smallest prime starting (in the most significant digits) with a(2n-1) (i.e., as a right concatenation of a(2n-1) and a number with no insignificant zeros); a(2n+1) = smallest prime ending in (the least significant digits) a(2n-1). Alternate left and right concatenation yielding primes.

3, 31, 131, 1319, 21319, 213193, 12213193, 122131939, 1122131939, 112213193957, 27112213193957, 271122131939573, 3271122131939573, 327112213193957339, 2327112213193957339, 232711221319395733969, 13232711221319395733969

Offset

1,1

Links

Table of n, a(n) for n=1..17.

Example

a(4) = 1319 staring with a(3) = 131 and a(5) = 21319 ending in a(4) = 1319.

Crossrefs

Cf. A053582, A069605, A069606, A069607, A069608, A069609, A069610, A069611, A069613, A069614.

Sequence in context: A119682 A267941 A069630 * A087389 A294394 A064055

Adjacent sequences: A069612 A069613 A069614 * A069616 A069617 A069618

Keyword

nonn,base,more

Author

Amarnath Murthy, Mar 27 2002

Extensions

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

Status

approved