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Revision History for A357023

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A357023

Semiprimes k such that k is congruent to 5 modulo k's index in the sequence of semiprimes.
(history; published version)

#32 by Giovanni Resta at Sun Oct 16 03:23:41 EDT 2022

STATUS

reviewed

approved

#31 by Michel Marcus at Sun Oct 16 01:43:22 EDT 2022

STATUS

proposed

reviewed

#30 by Lucas A. Brown at Sat Oct 15 18:16:16 EDT 2022

STATUS

editing

proposed

#29 by Lucas A. Brown at Sat Oct 15 18:16:14 EDT 2022

LINKS

Lucas A. Brown, <a href="/A357023/b357023.txt">Table of n, a(n) for n = 1..31</a>

STATUS

approved

editing

#28 by N. J. A. Sloane at Sat Oct 15 16:30:02 EDT 2022

STATUS

proposed

approved

#27 by Lucas A. Brown at Fri Oct 14 16:12:27 EDT 2022

STATUS

editing

proposed

#26 by Lucas A. Brown at Fri Oct 14 16:12:00 EDT 2022

DATA

4, 185, 206, 209, 27681, 3066905, 3067135, 3067795, 3067985, 348933197, 348933239, 348933251, 348933257, 348933269, 44690978141, 44690978162, 44690978519, 44690978561, 44690978617, 44690978869, 44690978981, 44690979457, 44690979527, 6553736049293

#25 by Lucas A. Brown at Fri Oct 14 16:11:03 EDT 2022

NAME

Semiprimes k such that k is congruent to 5 modulo k's index in the sequence of semiprimes.

#24 by Lucas A. Brown at Fri Oct 14 16:09:15 EDT 2022

NAME

allocated for Lucas A. Brown

Semiprimes k such that k is congruent to 5 modulo k's index in the sequence of semiprimes

DATA

OFFSET

1,1

COMMENTS

a(32) > 8040423200947.

LINKS

Lucas A. Brown, <a href="https://github.com/lucasaugustus/oeis/blob/main/semiprimemods.py">semiprimemods.py</a>.

FORMULA

a(n) = A001358(A106130(n)).

EXAMPLE

The 1st semiprime is 4, which is congruent to 5 (mod 1), so 4 is in the sequence.

The 2nd semiprime is 6, which is not congruent to 5 (mod 6), so 6 is not in the sequence.

The 60th semiprime is 185, which is congruent to 5 (mod 60), so 185 is in the sequence.

CROSSREFS

Cf. A001358, A106130.

KEYWORD

allocated

nonn,hard

AUTHOR

Lucas A. Brown, Oct 14 2022

STATUS

approved

editing

Discussion

Fri Oct 14

16:09

Lucas A. Brown: I have a b-file with terms up to index 31 ready to upload once this sequence is approved.

#23 by Lucas A. Brown at Fri Oct 14 16:09:15 EDT 2022

NAME

allocated for Lucas A. Brown

KEYWORD

recycled

allocated