A147298 -id:A147298 - cp's OEIS frontend

A147302 Numbers k where records occur in the expression log(k) / log(A147298(k)).

2, 9, 81, 128, 2401, 4375, 6436343

Offset: 1

Artur Jasinski, Nov 05 2008

Numbers a(n) such that a(n)/R(m a(n)(a(n)-m)) > a(n-1)/R(g a(n-1)(a(n-1)-g)) 0 < m < a(n) and 0 < g < a(n-1).
This sequence is list of successive records in the abc conjecture.
No more terms up to 10^20.
For smallest values of function rad(m*n*(n-m)) see A147298.
For biggest values of function rad(m*n*(n-m)) see A147299.
For numbers m for which rad(m*n*(n-m)) reaches a minimal value see A147300.
For numbers m for which rad(m*n*(n-m)) reaches a maximal value see A147301.

Carlos Rivera, Puzzle 901. A question about consecutive integers, The Prime Puzzles and Problems Connection.

Cf. A085152, A085153, A147298-A147307.

logmax = 0; aa = {}; Do[min = 10^100; max = 0; ile = 0; Do[If[GCD[m, n, n - m] == 1, ile = ile + 1; s = m n (n - m); k = FactorInteger[s]; g = 1; Do[g = g k[[p]][[1]], {p, 1, Length[k]}]; If[g > max, max = g; mmax = m]; If[g < min, min = g; mmin = m]], {m, 1, n - 1}]; If[(Log[n]/Log[min]) > logmax, logmax = (Log[n]/Log[min]); AppendTo[aa, n]; Print[{N[logmax], n, mmin, min, mmax, max}]; AppendTo[ff, n]], {n, 2, 2500}]; aa

A147303 Numbers k where records occur in expression Log[A147298(k)]/Log[k] k=2,3,4,...

Original entry on oeis.org

2, 3, 6, 7, 14, 15, 22, 30, 42, 62, 66, 70, 78, 102, 114, 158, 166, 182, 186, 210, 222, 230, 255, 258, 282, 318, 330, 402, 430, 438, 462, 470, 474, 494, 498, 510, 570, 582, 598, 690, 710, 786, 798, 822, 870, 906, 930, 942, 1002, 1038, 1074, 1110, 1122, 1146, 1158

Offset: 1

Artur Jasinski, Nov 06 2008

nonn

Limit k->Infinity Log[A147298(k)]/Log[k] = 2.

Values m for which records occur, see A147301.

Cf. A147298-A147302, A147304-A147307.

logmin = 10^10; logmax = 0; aa = {}; bb = {}; cc = {}; dd = {}; ee = {}; ff = {}; hh = {}; ii = {}; jj = {}; Do[min = 10^100; max = 0; Do[If[GCD[m, n, n - m] == 1, s = m n (n - m); k = FactorInteger[s]; g = 1; Do[g = g k[[p]][[1]], {p, 1, Length[k]}]; If[g > max, max = g; mmax = m]; If[g < min, min = g; mmin = m]], {m, 1, n - 1}]; AppendTo[aa, min]; If[(Log[n]/Log[min]) > logmax, logmax = (Log[n]/Log[min]); AppendTo[ee, {N[logmax], n, mmin, min, mmax, max}]; AppendTo[ff, n]]; If[(Log[n]/Log[min]) < logmin, logmin = (Log[n]/Log[min]); AppendTo[hh, {N[logmin], n, mmin, min, mmax, max}]; AppendTo[ii, n]]; AppendTo[bb, max]; AppendTo[dd, mmin], {n, 2, 1200}]; ii

A147307 Numbers A of the constrained search for ABC records described in A147306.

Original entry on oeis.org

1, 1, 1, 1, 1, 1, 5, 19, 41, 125, 23, 1, 1, 1, 95

Offset: 1

Artur Jasinski, Nov 09 2008

The sequences A147305, a(n) and A147307 are steered by searching for records in the ABC conjecture along increasing C confined as described in A147306, the main entry for these three sequences.

Cf. A085152, A085153, A147298-A147307.

a(n)+A147305(n) = A147306(n). gcd(a(n),A147305(n))=1.

Edited by R. J. Mathar, Aug 24 2009

A147638 The numbers B associated with the search for records in the ABC conjecture constrained as described in A147639.

Original entry on oeis.org

3, 7, 15, 27, 63, 125, 1701

Offset: 1

Artur Jasinski, Nov 09 2008

The standard way to search for records in the ABC conjecture is to run with the C parameter through all the integers A000027. If this search space is diluted by admitting only powers of 2 as in A147639, the sequence of records changes. This sequence here lists the B such that the triples (A=A147640(n), B=a(n), C=A147639(n)) locate records for this search restricting C to powers of 2.

Abderrahmane Nitaj, The ABC conjecture homepage

Cf. A085152, A085153, A147298-A147307, A147638-A147643.

Definition and commend edited by R. J. Mathar, Aug 28 2009

A147300 a(n) = smallest value of parameter m such that the function rad(mn(n - m)) has minimal value n=2,3,4,..., 0 < m < n where the function rad(k) (also called radical(k)) is the product of distinct prime divisors of k.

Original entry on oeis.org

1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 7, 1, 1, 1, 2, 1, 2, 1, 4, 5, 1, 9, 3, 1, 1, 11, 7, 1, 9, 1, 16, 1, 1, 1, 2, 1, 1, 1, 1, 25, 4, 5, 1, 1, 25, 9, 27, 1, 1, 1, 1, 1, 1, 1, 3, 1, 5, 1, 7, 1, 1, 25, 11, 1, 13, 1, 4, 1, 1, 1, 2, 1, 4, 5, 23, 7, 8, 1, 27, 11, 1, 13, 14, 1, 1, 17, 1, 1

Offset: 2

Artur Jasinski, Nov 05 2008

nonn

The function rad(k) is used in ABC conjecture applications.
For smallest values of the function rad(m n (n - m)) see A147298.
For the largest values of the function rad(m n (n - m)) see A147299.
For numbers m at which rad(m*n*(n - m)) reaches minimal value see A147300.
For numbers m at which rad(m*n*(n - m)) reaches maximal value see A147301.
For sequence in which each value log(n)/log(A147298(n)) reaches records see A147302.

Cf. A085152, A085153, A147298-A147307.

logmax = 0; aa = {}; bb = {}; cc = {}; dd = {}; ee = {}; ff = {}; gg \ = {}; Do[min = 10^100; max = 0; ile = 0; Do[If[GCD[m, n, n - m] == 1, ile = ile + 1; s = m n (n - m); k = FactorInteger[s]; g = 1; Do[g = g k[[p]][[1]], {p, 1, Length[k]}]; If[g > max, max = g; mmax = m]; If[g < min, min = g; mmin = m]], {m, 1, n - 1}]; AppendTo[aa, min]; AppendTo[bb, max]; AppendTo[cc, mmax]; AppendTo[dd, mmin]; AppendTo[gg, ile]; If[(Log[n]/Log[min]) > logmax, logmax = (Log[n]/Log[min]); AppendTo[ee, {N[logmax], n, mmin, min, mmax, max}]; Print[{N[logmax], n, mmin, min, mmax, max}]; AppendTo[ff, n]], {n, 2, 129}]; dd (* Artur Jasinski *)

A147643 Numbers A associated with the records of the merit function of the ABC conjecture admitting only C which are powers of 23.

Original entry on oeis.org

7, 17, 162, 2

Offset: 1

Artur Jasinski, Nov 09 2008

If records of the ABC merit function are listed scanning only parameters C of the form 23^x as described in A147642, a(n) is the value of A associated with B=A147641(n) and C=A147642(n).

OEIS Index entries for sequences related to the abc conjecture.

Cf. A085152, A085153, A147298-A147307, A147638-A147642.

a(n) = A147642(n)-A147641(n).

Edited by M. F. Hasler, Jan 16 2015

A143700 a(n) is the least odd number m minimizing A007947(m*(2^n-m)).

Original entry on oeis.org

1, 1, 1, 1, 5, 1, 3, 13, 169, 25, 243, 375, 11, 49, 7, 3, 18225, 71875, 4913, 1701, 144027, 1825, 3483, 2197, 9156027, 131989, 1103, 5103, 38525, 458703, 1523, 3483891, 19283525

Offset: 1

Artur Jasinski, Nov 10 2008

Smallest odd number a(n) such that product of distinct prime divisors of (2^n)*a(n)*(2^n - a(n)) is the smallest available for a(n) <= 2^x - a(n) < 2^x.
Product of distinct prime divisors of (2^n)*a(n)*(2^n - a(n)) is also called radical: rad((2^n)*a(n)*(2^n - a(n))).
For numbers 2^n - a(n) see A143701.
For minimal values of rad((2^n)*a(n)*(2^n - a(n))) see A143702.
Related to the abc conjecture. - M. F. Hasler, Nov 13 2008

Cf. A007947, A085152, A085153, A147298-A147307, A147638-A147643.

a = {{1, 1}}; aa = {1}; bb = {}; rr = {}; Do[logmax = 0; k = 2^x; w = Floor[(k - 1)/2]; Do[m = FactorInteger[n (k - n)]; rad = 1; Do[rad = rad m[[s]][[1]], {s, 1, Length[m]}]; log = Log[k]/Log[rad]; If[log > logmax, bmin = k - n; amax = n; logmax = log; r = rad], {n, 1, w, 2}]; Print[{x, amax}]; AppendTo[aa, amax]; AppendTo[bb, bmin]; AppendTo[rr, r]; AppendTo[a, {x, logmax}], {x, 2, 15}]; aa (* Artur Jasinski with assistance of M. F. Hasler *)

A143700(n) = {my(b=1, m=2^n-b); forstep(a=3, 2^(n-1), 2, A007947(a)*A007947(2^n-a)A007947((2^n-a)*b=a)); b; } \\ M. F. Hasler, Nov 13 2008

a(28)-a(33) from M. F. Hasler, Nov 13 2008

A147299 a(n) = largest value of the function rad(mn(n - m)) n=2,3,4,..., 0 < m < n where the function rad(k) (also called radical(k)) is the product of distinct prime divisors of k.

Original entry on oeis.org

2, 6, 6, 30, 30, 70, 30, 42, 210, 330, 210, 546, 462, 390, 110, 1190, 462, 1482, 910, 2310, 2310, 2990, 858, 770, 4290, 546, 2730, 6090, 6630, 7378, 510, 8778, 9690, 10010, 1938, 12210, 13566, 14586, 3990, 17138, 18354, 19866, 10626, 7590, 22678

Offset: 2

Artur Jasinski, Nov 05 2008

nonn

The function rad(k) is used in ABC conjecture applications.
For smallest values of the function rad(m n (n - m)) see A147298.
For numbers m at which rad(m*n*(n - m)) reaches minimal value see A147300.
For numbers m at which rad(m*n*(n - m)) reaches maximal value see A147301.
Sequence in which each value log(n)/log(A147298(n)) reaches records see A147302.

Ivan Neretin, Table of n, a(n) for n = 2..1000

Cf. A085152, A085153, A147298-A147307.

logmax = 0; aa = {}; bb = {}; cc = {}; dd = {}; ee = {}; ff = {}; gg \ = {}; Do[min = 10^100; max = 0; ile = 0; Do[If[GCD[m, n, n - m] == 1, ile = ile + 1; s = m n (n - m); k = FactorInteger[s]; g = 1; Do[g = g k[[p]][[1]], {p, 1, Length[k]}]; If[g > max, max = g; mmax = m]; If[g < min, min = g; mmin = m]], {m, 1, n - 1}]; AppendTo[aa, min]; AppendTo[bb, max]; AppendTo[cc, mmax]; AppendTo[dd, mmin]; AppendTo[gg, ile]; If[(Log[n]/Log[min]) > logmax, logmax = (Log[n]/Log[min]); AppendTo[ee, {N[logmax], n, mmin, min, mmax, max}]; Print[{N[logmax], n, mmin, min, mmax, max}]; AppendTo[ff, n]], {n, 2, 129}]; bb (* Artur Jasinski *)
Table[Max[Times @@ FactorInteger[#][[All, 1]] & /@ ((m = Range[1, n - 1])*(n - m)*n)], {n, 2, 46}] (* Ivan Neretin, May 21 2015 *)

A147301 a(n) = smallest value of parameter m such that the function rad(m n (n - m)) has maximal value n=2,3,4..., 0 < m < n where the function rad(k) (also called radical(k)) is the product of distinct prime divisors of k.

Original entry on oeis.org

1, 1, 1, 2, 1, 2, 3, 2, 3, 5, 5, 6, 3, 2, 5, 7, 7, 6, 7, 10, 7, 10, 11, 11, 11, 13, 13, 14, 13, 14, 15, 14, 15, 13, 17, 15, 17, 17, 19, 19, 19, 21, 21, 22, 17, 21, 19, 23, 21, 22, 23, 23, 23, 26, 23, 26, 23, 29, 29, 30, 29, 29, 31, 31, 31, 33, 33, 34, 33, 34, 35, 35, 35, 37, 37, 38

Offset: 2

Artur Jasinski, Nov 05 2008

nonn

Function rad(k) is used in ABC conjecture applications.
For smallest values of the function rad(m n (n - m)) see A147298.
For biggest values of the function rad(m n (n - m)) see A147299.
For numbers m for which rad(m n (n - m)) reaches a minimal value see A147300.
For numbers m for which rad(m n (n - m)) reaches a maximal value see A147301.
For the sequence in each value log(n)/log(A147298(n)) reached records see A147302.

Cf. A085152, A085153, A147298-A147307.

logmax = 0; aa = {}; bb = {}; cc = {}; dd = {}; ee = {}; ff = {}; gg \ = {}; Do[min = 10^100; max = 0; ile = 0; Do[If[GCD[m, n, n - m] == 1, ile = ile + 1; s = m n (n - m); k = FactorInteger[s]; g = 1; Do[g = g k[[p]][[1]], {p, 1, Length[k]}]; If[g > max, max = g; mmax = m]; If[g < min, min = g; mmin = m]], {m, 1, n - 1}]; AppendTo[aa, min]; AppendTo[bb, max]; AppendTo[cc, mmax]; AppendTo[dd, mmin]; AppendTo[gg, ile]; If[(Log[n]/Log[min]) > logmax, logmax = (Log[n]/Log[min]); AppendTo[ee, {N[logmax], n, mmin, min, mmax, max}]; Print[{N[logmax], n, mmin, min, mmax, max}]; AppendTo[ff, n]], {n, 2, 129}]; cc (* Artur Jasinski *)

A147306 Numbers C in successive records of the merit function of the ABC conjecture considering only C from A033845.

Original entry on oeis.org

6, 12, 18, 24, 36, 48, 54, 144, 384, 486, 648, 2304, 3888, 5832, 279936

Offset: 1

Artur Jasinski, Nov 09 2008

In a variant of the ABC conjecture (see A120498) we look at triples (A,B,C) restricted to A+B=C, gcd(A,B)=1, and at the merit function L(A,B,C)=log(C)/log(rad(A*B*C)), where rad() is the squarefree kernel A007947, as usual. Watching for records in L() as C runs through the integers generates A147302. In this sequence here, we admit only the C of the sequence A033845, which avoids some early larger records that would be created by unrestricted C, and leads to a slower increase of the L-values.
If the ABC conjecture is true this sequence is finite.
The associated numbers B for this case are A147305, the associated A are A147307.

			(A,B,C) = (1,5,6) defines the first record, L=0.5268.. (A,B,C)=(1,11,12) reaches L=0.5931..
(A,B,C) = (1,17,18) reaches L=0.6249.. The first C-number selected from A033845 that does not generate a new record is 72.

Cf. A085152, A085153, A147298-A147307.

Digits := 120 : A007947 := proc(n) local f,p; f := ifactors(n)[2] ; mul( op(1,p),p=f) ; end:
L := proc(A,B,C) local rad; rad := A007947(A*B*C) ; evalf(log(C)/log(rad)) ; end:
isA033845 := proc(n) local f,p; f := ifactors(n)[2] ; for p in f do if not op(1,p) in {2,3} then RETURN(false) ; fi; od: RETURN( (n mod 2 = 0 ) and (n mod 3 = 0 ) ) ; end:
crek := -1 : for C from 3 do if isA033845(C) then for A from 1 to C/2 do B := C-A ; if gcd(A,B) = 1 then l := L(A,B,C) ; if l > crek then print(C) ; crek := l ; fi; fi; od: fi; od: # R. J. Mathar, Aug 24 2009

Edited by R. J. Mathar, Aug 24 2009

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A147302 Numbers k where records occur in the expression log(k) / log(A147298(k)).

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A147303 Numbers k where records occur in expression Log[A147298(k)]/Log[k] k=2,3,4,...

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A147307 Numbers A of the constrained search for ABC records described in A147306.

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A147638 The numbers B associated with the search for records in the ABC conjecture constrained as described in A147639.

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A147300 a(n) = smallest value of parameter m such that the function rad(m*n*(n - m)) has minimal value n=2,3,4,..., 0 < m < n where the function rad(k) (also called radical(k)) is the product of distinct prime divisors of k.

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A147643 Numbers A associated with the records of the merit function of the ABC conjecture admitting only C which are powers of 23.

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A143700 a(n) is the least odd number m minimizing A007947(m*(2^n-m)).

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A147299 a(n) = largest value of the function rad(m*n*(n - m)) n=2,3,4,..., 0 < m < n where the function rad(k) (also called radical(k)) is the product of distinct prime divisors of k.

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A147301 a(n) = smallest value of parameter m such that the function rad(m n (n - m)) has maximal value n=2,3,4..., 0 < m < n where the function rad(k) (also called radical(k)) is the product of distinct prime divisors of k.

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A147306 Numbers C in successive records of the merit function of the ABC conjecture considering only C from A033845.

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A147300 a(n) = smallest value of parameter m such that the function rad(mn(n - m)) has minimal value n=2,3,4,..., 0 < m < n where the function rad(k) (also called radical(k)) is the product of distinct prime divisors of k.

A147299 a(n) = largest value of the function rad(mn(n - m)) n=2,3,4,..., 0 < m < n where the function rad(k) (also called radical(k)) is the product of distinct prime divisors of k.