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A019519 Concatenate odd numbers. 10
1, 13, 135, 1357, 13579, 1357911, 135791113, 13579111315, 1357911131517, 135791113151719, 13579111315171921, 1357911131517192123, 135791113151719212325, 13579111315171921232527, 1357911131517192123252729, 135791113151719212325272931 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

REFERENCES

X. Chen and M. Le, The Module Periodicity of Smarandache Concatenated Odd Sequence, Smarandache Notions Journal, Vol. 9, No. 1-2. 1998, 103-104.

H. Ibstedt, A Few Smarandache Sequences, Smarandache Notions Journal, Vol. 8, No. 1-2-3, 1997, 170-183..

S. Smarandoiu, Convergence of Smarandache continued fractions, Abstract 96T-11-195, Abstracts Amer. Math. Soc., 17 (No. 4, 1996), 680.

LINKS

Table of n, a(n) for n=1..16.

F. Smarandache, Definitions, Solved and Unsolved Problems, Conjectures, ... , edited by M. Perez, Xiquan Publishing House 2000

F. Smarandache, Collected Papers, Vol. II, Tempus Publ. Hse., Bucharest, Romania, 1996

Eric Weisstein's World of Mathematics, Consecutive Number Sequences

FORMULA

Sequence grows like 10^K, where K = 2+floor[log_10 n] + floor[log_10 a(n-1)]. More generally we may consider a(n)= F(a(n-1),n)*B^K + G(a(n-1),n); K = floor[log_B H(a(n-1),n)]; F(a(n-1),n); G(a(n-1),n); H(a(n-1),n) integer polynomials; B integer. - Ctibor O. Zizka, Mar 08 2008

a(n)=a(n-1)*10^[log10(2*n-1)+1]+2*n-1, with a(1)=1. [From Paolo P. Lava, Mar 05 2010]

MATHEMATICA

nn=20; With[{odds=Range[1, 2nn+1, 2]}, Table[FromDigits[Flatten[ IntegerDigits/@ Take[odds, n]]], {n, nn}]] (* Harvey P. Dale, Aug 14 2014 *)

CROSSREFS

Primes are in A048847, while their indices are in A046036.

Sequence in context: A132930 A130774 A179619 * A243216 A112225 A069511

Adjacent sequences:  A019516 A019517 A019518 * A019520 A019521 A019522

KEYWORD

base,nonn,easy

AUTHOR

R. Muller

EXTENSIONS

More terms from Erich Friedman.

More terms from Harvey P. Dale, Aug 14 2014

STATUS

approved

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Last modified October 21 16:25 EDT 2019. Contains 328302 sequences. (Running on oeis4.)