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A023149 Numbers k such that prime(k) == 7 (mod k). 13
1, 2, 4, 6, 18, 36, 78, 191, 6456, 6457, 40080, 40081, 637324, 637326, 637344, 10553425, 10553434, 10553477, 10553502, 10553573, 10553854, 27066988, 27067126, 69709680, 69709736, 69709940, 465769818, 3140421716, 3140421740, 3140421743 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Giovanni Resta, Table of n, a(n) for n = 1..71

MATHEMATICA

p = 1; Do[ If[ Mod[p = NextPrime[p], n] == 7, Print[n]], {n, 1, 10^9}] (* Robert G. Wilson v, Feb 18 2004 *)

PROG

(Sage)

def A023149(max) :

    terms = []

    p = 2

    for n in range(1, max+1) :

        if (p - 7) % n == 0 : terms.append(n)

        p = next_prime(p)

    return terms

# Eric M. Schmidt, Feb 05 2013

CROSSREFS

Cf. A171434, A092049, A023143, A023144, A023145, A023146, A023147, A023148, A023150, A023151, A023152.

Sequence in context: A088174 A052930 A098853 * A085146 A066894 A233919

Adjacent sequences:  A023146 A023147 A023148 * A023150 A023151 A023152

KEYWORD

nonn

AUTHOR

David W. Wilson

EXTENSIONS

More terms from Robert G. Wilson v, Feb 18 2004

a(27)-a(31) from Robert G. Wilson v, Feb 22 2006

First four terms inserted by Eric M. Schmidt, Feb 05 2013

STATUS

approved

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Last modified May 11 16:48 EDT 2021. Contains 343805 sequences. (Running on oeis4.)