The On-Line Encyclopedia of Integer Sequences (OEIS)

Revision History for A177820

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A177820

Numbers k such that k^3 divides 20^(k^2) + 1.
(history; published version)

#6 by Susanna Cuyler at Sun Jun 06 09:03:36 EDT 2021

STATUS

reviewed

approved

#5 by Joerg Arndt at Sun Jun 06 05:18:25 EDT 2021

STATUS

proposed

reviewed

#4 by Jon E. Schoenfield at Sun Jun 06 02:53:35 EDT 2021

STATUS

editing

proposed

#3 by Jon E. Schoenfield at Sun Jun 06 02:53:32 EDT 2021

NAME

Numbers n k such that nk^3 divides 20^(nk^2) + 1.

CROSSREFS

Cf. A127263 = numbers n such that n(k^3 divide divides 2^(nk^2) + 1).

Cf. A128677 = Least (least k > p such that (kpk*p)^3 divides (p-1)^(kpk*p)^2+1, where p = Prime[prime(n]) > 2).

STATUS

approved

editing

#2 by Russ Cox at Sat Mar 31 13:20:40 EDT 2012

AUTHOR

_Alexander Adamchuk (alex(AT)kolmogorov.com), _, May 14 2010

Discussion

Sat Mar 31

13:20

OEIS Server: https://oeis.org/edit/global/879

#1 by N. J. A. Sloane at Tue Jun 01 03:00:00 EDT 2010

NAME

Numbers n such that n^3 divides 20^(n^2)+1.

DATA

1, 3, 7, 21, 381, 903, 921, 2667, 5789, 6447, 17367, 18543, 73703, 114681, 116967, 208443, 221109, 277221, 746781, 797349, 818769, 855141, 871347, 1459101, 2205609, 2354961, 5090367, 5331669, 5692701, 6099429, 7611387, 8710041

OFFSET

1,2

CROSSREFS

Cf. A127263 = numbers n such that n^3 divide 2^(n^2)+1.

Cf. A128678, A128679, A128680, A128681, A128682, A128683, A128684, A128685.

Cf. A177813, A177814, A177816, A177817, A177818, A177819, A177820.

Cf. A128677 = Least k>p such that (kp)^3 divides (p-1)^(kp)^2+1, where p = Prime[n]>2.

KEYWORD

nonn,new

AUTHOR

Alexander Adamchuk (alex(AT)kolmogorov.com), May 14 2010

STATUS

approved