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A320223 First occurrence of the n-th prime in A075019. 0
2, 3, 25, 43, 157, 19, 271, 229, 49, 31, 181, 91, 397, 481, 301, 127, 511, 439, 2701, 37, 79, 253, 793, 1531, 1237, 523, 1867, 637, 5293, 13, 7, 103, 3871, 3361, 4387, 199, 829, 2341, 2143, 367, 6511, 3967, 6391, 5617, 7711, 1273, 3217, 1621, 8767, 3157, 3013 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Conjecture: All primes are present in A075019.

Records: 2, 3, 25, 43, 157, 271, 397, 481, 511, 2701, 5293, 6511, 7711, 8767, 11941, 12061, 25651, 30901, 30919, 47239, 64033, 145591, etc.

LINKS

Table of n, a(n) for n=1..51.

EXAMPLE

a(1) = 2 since the first prime, 2, divides 12;

a(2) = 3 since the second prime, 3, divides 123;

a(3) = 25 since the third prime, 5, divides 12345678910111213141516171819202122232425; although 5 also divides 12345, so does 3 which is less than 5.

MATHEMATICA

f[n_] := f[n] = Block[{p = Prime@ n, k = 1}, While[s = FromDigits@ Flatten[ IntegerDigits@# & /@ Range@ k]; Mod[s, p] > 0 || Union[Mod[s, Prime@ Range[n - 1]]][[1]] == 0, k += 2]; k]; f[1] = 2; Array[f, 51]

CROSSREFS

Cf. A000040, A075019.

Sequence in context: A291262 A307922 A048674 * A296275 A295328 A281169

Adjacent sequences:  A320220 A320221 A320222 * A320224 A320225 A320226

KEYWORD

nonn,base

AUTHOR

Robert G. Wilson v, Oct 07 2018

STATUS

approved

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Last modified July 23 11:44 EDT 2019. Contains 325254 sequences. (Running on oeis4.)