id:A080156 - OEIS Search Results

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Values of n corresponding to the terms in sequence A080155. For any k, the concatenation of the a(1) to a(k)-th primes is prime and each value of k is the smallest for which this is true.

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1, 2, 5, 11, 15, 50, 54, 106, 148, 149, 156, 188, 200, 211, 248, 326, 359, 374, 417, 467, 699, 798, 891, 966, 1038, 1519, 1542, 1578, 1831, 1908, 1982, 2079, 2305, 2640, 2660, 2845, 3078, 3145, 3760, 3777, 3835, 4538, 4630, 4991 (list; graph; listen)

	OFFSET	`0,2`
	FORMULA	`A080155(n) = ithprime(a(n)).`
	MAPLE	`with(numtheory): pout := [2]: nout := [1]: for n from 2 to 5000 do: p := ithprime(n): d := parse(cat(seq(pout[i], i=1..nops(pout)), p)): if (isprime(d)) then pout := [op(pout), p]: nout := [op(nout), n]: fi: od: nout;`
	CROSSREFS	`Cf. A073640, A080152-A080155.` `Sequence in context: A097055 A026228 A003420 this_sequence A082083 A024917 A081402` `Adjacent sequences: A080153 A080154 A080155 this_sequence A080157 A080158 A080159`
	KEYWORD	`nonn`
	AUTHOR	`Mark Hudson (mrmarkhudson(AT)hotmail.com), Jan 31 2003`

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Last modified December 10 00:48 EST 2009. Contains 170565 sequences.

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