[Fwd: SEQ FROM Peter Pein]

[Peter Pein]

Dear Neil,

I obviously made a mistake, when entering the sequence number which I've
got from the dispenser. This should become A131903.

sorry,
Peter

The following is a copy of the email message that was sent to njas
containing the sequence you submitted.

All greater than and less than signs have been replaced by their html
equivalents.  They will be changed back when the message is processed.

This copy is just for your records.  No reply is expected.
 Subject: NEW SEQUENCE FROM Peter Pein


%I A000001
%S A000001 3, 5, 7, 8, 9, 10, 11, 13, 14, 15, 17, 18, 19, 20, 21, 22,
23, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 37, 38, 39, 40, 41, 42,
43, 44, 45, 46, 47, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 61, 62, 63
%N A000001 Those integers for which a smaller positive integer exists
which has the same number of divisors
%F A000001 a(n)= n-th element of {x>0, there exists a k with
0<k<x and the same number of divisors as x)
%e A000001 a(4)=8 because it is the fourth integer for which a smaller
integer with the same number of divisors exists (after 3, 5 and 7).
divisors of 8 are 1,2,4,8 which are four and the divisors of 6 which is
less than 8 are (1, 2, 3, 6) which are four.
%t A000001 Clear[tmp];
Function[n, If[Head[#1] === tmp, #1 = n; Unevaluated[Sequence[]], n] &
   [tmp[DivisorSigma[0, n]]]] /@ Range[64]
%Y A000001 Cf. A069822, A131902-A131908
%O A000001 1
%K A000001 ,easy,nonn,
%A A000001 Peter Pein (petsie at dordos.net), Jul 26 2007
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