A019524 Duplicate terms of A007908.

11, 1212, 123123, 12341234, 1234512345, 123456123456, 12345671234567, 1234567812345678, 123456789123456789, 1234567891012345678910, 12345678910111234567891011, 123456789101112123456789101112

Offset

1,1

References

F. Iacobescu, Smarandache Partition Type and Other Sequences, Bull. Pure Appl. Sciences, Vol. 16E, No. 2 (1997), pp. 237-240.

Links

Table of n, a(n) for n=1..12.

Eric Weisstein's World of Mathematics, Smarandache Sequences

F. Smarandache, Collected Papers, Vol. II

F. Smarandache, Sequences of Numbers Involved in Unsolved Problems.

Formula

a(n) = A007908(n)*(1 + 10^A058183(n)) = (n + a(n - 1)*10^L(n)/(1 + 10^(n*L(n - 1) - (10^L(n - 1) - 1)/9)))*(1 + 10^((n + 1)*L(n) - (10^L(n) - 1)/9)) where L(n) = floor(log_10(10n)). - Henry Bottomley, Nov 17 2000 (may need to be adapted for change in offset)

Crossrefs

Sequence in context: A237695 A180581 A233012 * A274766 A261138 A259937

Adjacent sequences: A019521 A019522 A019523 * A019525 A019526 A019527

Keyword

nonn

Author

R. Muller

Status

approved