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A035092 Smallest k - dependent on n - such that (n^2)*k+1 is prime where k is the subscript of the progressions. 7
1, 1, 2, 1, 4, 1, 4, 3, 2, 1, 6, 3, 4, 1, 8, 1, 12, 4, 30, 1, 2, 3, 24, 1, 18, 1, 2, 4, 12, 2, 16, 12, 2, 3, 6, 1, 4, 13, 6, 1, 10, 2, 12, 6, 2, 6, 4, 8, 6, 9, 6, 9, 28, 1, 4, 1, 10, 3, 6, 4, 46, 4, 4, 3, 4, 1, 4, 3, 22, 6, 10, 2, 4, 1, 2, 7, 22, 3, 6, 4, 6, 3, 10, 1, 4, 3, 2, 4, 6, 1, 10, 4, 2, 1 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

COMMENTS

This is one possible generalization of "the least prime problem" for nk+1 arithmetic progression when n is replaced by n^2, a special difference.

LINKS

Table of n, a(n) for n=1..94.

Index entries for sequences related to primes in arithmetic progressions

EXAMPLE

a(40) = 1 because in 1600k + 1 at k = 1, 1601 is the smallest prime; a(61)=46 because in 46*46*k+1 sequence the first prime appears at k=46, it is 171167.

PROG

(PARI)

a(n)=k=1; while(!isprime(k*n^2+1), k++); k

vector(100, n, a(n)) \\ Derek Orr, Oct 01 2014

CROSSREFS

Analogous case is A034693. See also A005574 and A002496.

Sequence in context: A029205 A229340 A072721 * A160598 A107457 A112350

Adjacent sequences:  A035089 A035090 A035091 * A035093 A035094 A035095

KEYWORD

nonn,easy

AUTHOR

Labos Elemer

STATUS

approved

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Last modified December 3 20:40 EST 2016. Contains 278745 sequences.