A085944 Let S = 12345678901234567890123456..., the cyclic concatenation of digits; partition this string into distinct squarefree numbers. To avoid leading zeros, no member may end with the digit 9.

1, 2, 3, 4567, 890, 123, 45678, 901, 23, 4567890, 1234, 5, 6, 7, 89012345, 67, 89012345678, 90123, 45678901, 2345, 678, 901234, 5678, 9012345, 67890, 12345, 678901, 2345678, 901234567, 8901234567890, 1234567, 8901234567890123

Offset

1,2

Links

Table of n, a(n) for n=1..32.

Example

a(4) = 4567 because 4567 is squarefree, while 4, 45 and 456 are not.
a(5) = 890 because 89 would cause a(6) to have a leading 0.

Prog

(PARI) used = matrix(9, 60); x = 1; for (n = 1, 80, num = x; s = x; d = 1; while (used[s, d] || !issquarefree(num) || x == 9, x = (x + 1)%10; num = 10*num + x; d++); print1(num, ", "); used[s, d] = 1; x++); \\ David Wasserman, Feb 14 2005

Crossrefs

Cf. A085943.

Sequence in context: A068661 A271631 A068826 * A137078 A146026 A115640

Adjacent sequences: A085941 A085942 A085943 * A085945 A085946 A085947

Keyword

base,nonn

Author

Amarnath Murthy, Jul 14 2003

Extensions

Corrected and extended by David Wasserman, Feb 14 2005

Status

approved