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A056740 Odd numbers k such that 2^k mod k = 2^(k+2) mod (k-2) is also an odd number. 0
135, 1423249, 31491395, 55519333, 1065373685, 3559609381 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..6.

Joe K. Crump, 2^n mod n

EXAMPLE

135 is a term because 2^135 mod 135 = 53 and 2^137 mod 133 = 53.

PROG

(PARI) isok(n) = {va = Mod(2, n)^n; (lift(va) % 2) && (lift(va) == lift(Mod(2, n-2)^(n+2))); } \\ Michel Marcus, Sep 02 2013

CROSSREFS

Cf. A015911.

Sequence in context: A106175 A203625 A051307 * A065663 A269062 A270301

Adjacent sequences: A056737 A056738 A056739 * A056741 A056742 A056743

KEYWORD

nonn,more

AUTHOR

Joe K. Crump (joecr(AT)carolina.rr.com), Aug 25 2000

EXTENSIONS

a(6) and title clarified by Sean A. Irvine, May 04 2022

STATUS

approved

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Last modified February 7 12:18 EST 2023. Contains 360116 sequences. (Running on oeis4.)