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A173149 Numbers n such that max(tau(n),tau(n+1),tau(n+2))- min(tau(n),tau(n+1),tau(n+2)) = 1. 1
1, 2, 3, 8, 14, 25, 121, 841, 1442, 6241, 8281, 16641, 20164, 24962, 26894, 28561, 46225, 55225, 58564, 65534, 67081, 73441, 93025, 104329, 110888, 116281, 143641, 149768, 155236, 212521, 235225, 252003, 271441, 279841, 284089, 293762, 293763 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,2
LINKS
EXAMPLE
For n = 1, max(tau(1),tau(2),tau(3)) - min(tau(1),tau(2),tau(3)) = max(1,2,2) - min(1,2,2) = 1.
For n = 121, max(tau(121),tau(122),tau(123)) - min(tau(121),tau(122),tau(123)) = max(1,2,2) - min(1,2,2) = 1
MAPLE
with(numtheory):for n from 1 to 1500000 do; if max(tau(n), tau(n+1), tau(n+2))- min(tau(n), tau(n+1), tau(n+2))= 1 then print(n); else fi ; od;
MATHEMATICA
Select[Range[10^6], Max[(d = DivisorSigma[0, #+{0, 1, 2}])] - Min[d] == 1 &] (* Amiram Eldar, Aug 14 2019 *)
CROSSREFS
Sequence in context: A022951 A247124 A171237 * A128305 A328881 A298349
KEYWORD
nonn
AUTHOR
Michel Lagneau, Feb 11 2010, Feb 13 2010
STATUS
approved

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Last modified April 12 22:48 EDT 2024. Contains 371639 sequences. (Running on oeis4.)