[seqfan] Re: Ramanujan sequence A067128.

Vladimir Shevelev shevelev at bgu.ac.il
Mon May 9 12:28:20 CEST 2016


Dear SeqFans,

Yesterday, Peter have sent me many
zero terms and I thought that it is better
to change the sequence by the following
calculated by Peter:

Numbers n such that the difference 
A067128(n+1) - A067128(n) is not in A067128. 
 
 47, 89, 93, 96, 105, 111, 112, 120, 123, 139, 
143, 150, 151, 155, 161, 162, 168, 170, 172, 
176, 177, 185, 186, 193, 194, 195, 199, 202, 
203, 204, 216, 223, 224, 227, 234, 236, 239, 
240, 245, 246, 247, 253, 254, 260, 263, 264, 
266, 271, 273, 274, 276, 280, 289 

Another idea of sequence is "Smallest
k>=1 such that A067128(n+k)-A067128(n)
is in A067128," containing the first 46 1's.

Best regards,
Vladimir

________________________________________
From: SeqFan [seqfan-bounces at list.seqfan.eu] on behalf of Vladimir Shevelev [shevelev at exchange.bgu.ac.il]
Sent: 08 May 2016 18:42
To: seqfan at list.seqfan.eu
Subject: [seqfan] Ramanujan sequence A067128.

Dear SeqFans,

Considering sequence A067128:
"Ramanujan's largely composite numbers,
defined to be n such that d(n) >= d(k)
for k = 1 to n-1",
I submitted A272879:
"If A067128(n+1) - A067128(n) is in A067128,
then a(n) is its position in A067128, otherwise
a(n)=0."
Using table, by handy I calculated 72 terms
and found only a(47)=0. I wonder, what are
the following zero terms?

Best regards,
Vladimir


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