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A019518 Smarandache-Wellin numbers: a(n) = concatenation of first n primes (written in decimal system). 67
2, 23, 235, 2357, 235711, 23571113, 2357111317, 235711131719, 23571113171923, 2357111317192329, 235711131719232931, 23571113171923293137, 2357111317192329313741, 235711131719232931374143, 23571113171923293137414347 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

REFERENCES

R. Crandall and C. Pomerance, Prime Numbers: A Computational Perspective, Springer, NY, 2001; see p. 72. [The 2002 printing states incorrectly that a(719) is prime. Cf. A046035.]

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

M. Le, On Smarandache Concatenated Sequences I: Prime Power Sequences, Smarandache Notions Journal, Vol. 9, No. 1-2, 1998, 129-130.

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

LINKS

Reinhard Zumkeller, Table of n, a(n) for n = 1..300

M. Fleuren, Factoring of the Smarandache Concatenated Prime Sequence.

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

Eric Weisstein's World of Mathematics, Consecutive Number Sequences

Eric Weisstein's World of Mathematics, Copeland-Erdős Constant

EXAMPLE

E.g. a(6) = 2_3_5_7_11_13 = 23571113.

MATHEMATICA

ConsecutivePrimes[n_] := FromDigits[Flatten[IntegerDigits /@ Prime[Range[n]]]] (from Eric Weisstein)

Table[FromDigits[Flatten[IntegerDigits[Prime[Range[i]]]]], {i, 15}] (* Jayanta Basu, May 30 2013 *)

PROG

(PARI) s=""; for(n=1, 30, print1(s=Str(s, prime(n))", ")) \\ Contribution from Cino Hilliard simplified by M. F. Hasler, Oct 06 2013

(PARI) A019518(n)=eval(concat(concat([""], primes(n)))) \\ Faster than concat(apply(s->Str(s), primes(n))) or forprime(...s=Str(s, p)). - M. F. Hasler, Oct 06 2013

(Haskell)

a019518 n = a019518_list !! (n-1)

a019518_list = map read $ scanl1 (++) $ map show a000040_list :: [Integer]

-- Reinhard Zumkeller, Mar 03 2014

CROSSREFS

For the primes in this sequence see A069151. For where the primes occur see A046035. See also A046284. A068670 gives number of digits.

Cf. A000040, A038394.

Sequence in context: A098739 A091762 A054261 * A048677 A132933 A220373

Adjacent sequences:  A019515 A019516 A019517 * A019519 A019520 A019521

KEYWORD

base,nonn

AUTHOR

R. Muller

STATUS

approved

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Last modified July 28 16:32 EDT 2014. Contains 245003 sequences.