A069621 a(1) = 9; 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). Alternate left and right concatenation yielding primes.

9, 97, 197, 1973, 31973, 319733, 3319733, 331973311, 6331973311, 633197331131, 5633197331131, 563319733113127, 6563319733113127, 65633197331131279, 3465633197331131279, 346563319733113127933, 18346563319733113127933

Offset

1,1

Links

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

Example

a(4) = 1973 staring with a(3) =197 and a(5) = 31973 ending in a(4) = 1973.

Crossrefs

Cf. A053582, A069605, A069606, A069607, A069608, A069609, A069610, A069611, A069613, A069614, A069615, A069616, A069617, A069618, A069619, A069620.

Sequence in context: A331113 A158489 A069636 * A284668 A232229 A240780

Adjacent sequences: A069618 A069619 A069620 * A069622 A069623 A069624

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