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# User talk:Eric Angelini

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## A conjectured permutation (proof?) of the nonnegative composite numbers interleaved with the sequence of primes

---------- Forwarded message ---------- From: Eric Angelini <Eric.Angelini@kntv.be> To: Sequence Fanatics Discussion list <seqfan@list.seqfan.eu> Cc: Date: Mon, 14 Jan 2013 18:19:53 +0100 Subject: [seqfan] Primes and prime sums Hello Seq-Fans, Write down the prime numbers: 2, 3, 5, 7, 11, 13, 17, 19, 23, ... Insert between two primes the smallest integer not yet present in the sequence such that two neighboring integers sum up to a prime. I think the sequence starts: 2,0,3,8,5,6,7,12,11,18,13,26,17,... Best, É.

I added a mention of your interesting idea in:

This is possibly a permutation of zero and the nonnegative composite numbers (proof?) interleaved with the sequence of primes, thus possibly a permutation of the nonnegative integers, except for the unit 1 which is not included.

If you considered:

Write down the [positive] odd noncomposites:

- {1, 3, 5, 7, 11, 13, 17, 19, 23, ...}

Insert between two [positive] odd noncomposites the smallest [positive] integer not yet present in the sequence such that two neighboring integers sum up to a prime.

You'd possibly get a permutation of the positive integers (proof?):

- {1, 2, 3, 8, 5, 6, 7, 12, 11, 18, 13, 26, 17, ...}

In either case, those are interesting sequences, and also the sequences of interleaved composite numbers. — Daniel Forgues 21:23, 20 January 2013 (UTC)

- Oops, the odd composites can't obviously be there. I really fumbled there... I'd really appreciate if you removed that part... (Since this is your talk page, only you can decide that...) — Daniel Forgues 03:17, 21 January 2013 (UTC)

## A conjectured permutation (proof?) of the primes interleaved with the sequence of nonprime numbers

---------- Forwarded message ---------- From: Eric Angelini <Eric.Angelini@kntv.be> To: Sequence Fanatics Discussion list <seqfan@list.seqfan.eu> Cc: Alexandre Wajnberg <alexandre.wajnberg@skynet.be> Date: Tue, 15 Jan 2013 11:49:33 +0100 Subject: [seqfan] Non-primes and non-prime sums Hello Seq-Fans, Write down the non prime numbers: 1, 4, 6, 8, 9, 10, 12, 14, 15, 16, 18, ... Insert between two non-primes the smallest prime not yet present in the sequence such that two neighboring integers sum to a non-prime. I think the sequence starts: 1,5,4,2,6,43,8,7,9,11,10,23,12,13,14,31,15,17,16,... Best, É.

I added a mention of your interesting idea in:

I hope I'm not fumbling this time! — Daniel Forgues 03:17, 21 January 2013 (UTC)

## Towards an index of your SeqFan/OEIS contributions

Hello Eric (and anyone who comes to read this page),

I think it would be time (but I don't have that much...) to make an index of your contributions, maybe using some classifications like

- (p) - permutations of the integers
- (b) - based on digits in base 10 (or another base)
- (d) - based on divisibility (not mutually exclusive with (d)...)
- (s) - self describing
- (s')- not self describing (if any?)

but I don't know what would be the most relevant such "categorization" or any other/better idea to start such a list... — MFH 02:19, 30 September 2014 (UTC)