login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo

Please make a donation to keep the OEIS running. We are now in our 56th year. In the past year we added 10000 new sequences and reached almost 9000 citations (which often say "discovered thanks to the OEIS").
Other ways to donate

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A090481 Primes p such that tau(p-1)+tau(p+1) is larger than for any previous term. (Smallest prime sandwiched between more composite numbers.) 7
2, 3, 5, 7, 11, 17, 19, 29, 41, 71, 179, 181, 239, 419, 701, 839, 881, 1259, 1871, 2161, 2521, 4159, 5039, 7561, 10079, 13441, 13859, 20161, 22679, 30241, 35281, 45361, 55439, 65519, 110879, 138599, 151201, 166319, 226799, 262079, 327599, 332641 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Donovan Johnson, Table of n, a(n) for n = 1..100

EXAMPLE

17 follows 11 and 13 is not a term as tau(10) + tau(12) = tau(12) + tau(14) = 10.

MATHEMATICA

a = {}; t = 0; Do[p = Prime[n]; s = DivisorSigma[0, p - 1] + DivisorSigma[0, p + 1]; If[s > t, t = s; AppendTo[a, p]], {n, 1, 10^5}]; a (* Robert G. Wilson v, Dec 04 2003 *)

CROSSREFS

Cf. A090482, A000005.

Sequence in context: A228424 A335325 A189828 * A094342 A164641 A058982

Adjacent sequences:  A090478 A090479 A090480 * A090482 A090483 A090484

KEYWORD

nonn

AUTHOR

Amarnath Murthy, Dec 02 2003

EXTENSIONS

More terms from Robert G. Wilson v, Dec 04 2003

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified December 2 10:39 EST 2020. Contains 338876 sequences. (Running on oeis4.)