OFFSET
1,1
COMMENTS
Conjecture: sequence is finite.
EXAMPLE
a(3) = 271, 270 = 3^3*10 and 272 = 2^3*34. 271 is the smallest such number.
a(4) = 1249, 1248 =2^4*78, 1250 = 5^4*2. 1250 is the smallest such number.
MATHEMATICA
PrimeExponents[n_] := Max[ Flatten[ Table[ # [[2]], {1}] & /@ FactorInteger[n]]]; NextPrim[n_] := Block[{k = n + 1}, While[ !PrimeQ[k], k++ ]; k]; a = Table[0, {15}]; p = 1; Do[p = NextPrim[p]; b = Min[ PrimeExponents[p - 1], PrimeExponents[p + 1]]; If[ a[[b]] == 0, a[[b]] = p; Print[b, " ", p]], {n, 1, 70000000}]; a
CROSSREFS
KEYWORD
nonn
AUTHOR
Amarnath Murthy, Aug 17 2003
EXTENSIONS
Edited and extended by Robert G. Wilson v, Aug 18 2003
a(5) corrected. a(13)-a(22) from Donovan Johnson, Sep 02 2008
STATUS
approved