cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

Previous Showing 11-14 of 14 results.

A062875 Records in A046112 (or A006339).

Original entry on oeis.org

1, 5, 25, 125, 3125, 15625, 390625, 1953125, 48828125, 6103515625, 30517578125, 3814697265625, 95367431640625, 476837158203125, 11920928955078125, 1490116119384765625, 186264514923095703125, 931322574615478515625, 116415321826934814453125
Offset: 1

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Author

Keywords

Comments

A111333 gives where records occur in A046112; A102781 gives where records occur in A006339.

Crossrefs

Programs

  • Python
    from sympy import prime
    def A062875(n): return 5**(prime(n)-1>>1) # Chai Wah Wu, Aug 02 2024

Formula

a(n) = A046112(A111333(n)) = A006339(A102781(n)).
a(n) = 5^(A111333(n)-1) = 5^A102781(n).

Extensions

Edited and extended by Ray Chandler, Jan 05 2012

A062876 Numbers of lattice points corresponding to incrementally largest circle radii in A062875.

Original entry on oeis.org

4, 12, 20, 28, 44, 52, 68, 76, 92, 116, 124, 148, 164, 172, 188, 212, 236, 244, 268, 284, 292, 316, 332, 356, 388, 404, 412, 428, 436, 452, 508, 524, 548, 556, 596, 604, 628, 652, 668, 692, 716, 724, 764, 772, 788, 796, 844, 892, 908, 916, 932, 956, 964
Offset: 1

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Author

Keywords

Comments

For n = 1 and n >= 3, a(n) is the smallest nonsquarefree number divisible by prime(n). - David James Sycamore, Jun 15 2024

Crossrefs

Programs

Formula

a(n) = A017113(A111333(n)-1) = 8*A111333(n) - 4.
For n >= 2 a(n) = 4*A000040(n) (a term in A013929). - David James Sycamore, Jun 15 2024

Extensions

Edited and extended by Ray Chandler, Jan 05 2012

A341351 a(n) = A048673(A181815(n)).

Original entry on oeis.org

1, 2, 5, 3, 14, 8, 41, 23, 4, 122, 13, 68, 11, 365, 38, 203, 32, 1094, 113, 18, 608, 6, 63, 95, 3281, 338, 53, 1823, 17, 188, 284, 9842, 1013, 158, 5468, 50, 563, 25, 851, 29525, 88, 3038, 28, 313, 473, 16403, 149, 1688, 74, 2552, 88574, 263, 9113, 7, 83, 938, 1418, 49208, 446, 5063, 221, 7655, 265721, 788, 27338, 20
Offset: 1

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Author

Keywords

Comments

Maxima are in A007051 and appear at n in A025488, which are the indices of 2^k in A025487. 2^k is idempotent via A181815 but transformed by A003961 to 3^n, which are rendered by A048673 to (3^n + 1)/2.
Local minima are in A111333 and appear at n in A098719, which are the indices of P(k) = A002110(k) in A025487. P(k) is transformed by A181815 to p_k = A000040(k), which become p_(k+1) under A003961. Therefore these become (p_(k+1)+1)/2 via A048673.

Crossrefs

Cf. A341352 (inverse).
Cf. A007051 (record values).

Programs

  • Mathematica
    a025487[n_] := {{1}}~Join~Block[{lim = Product[Prime@ i, {i, n}], ww = NestList[Append[#, 1] &, {1}, n - 1]}, Map[Block[{w = #, k = 1}, Sort@ Prepend[If[Length@ # == 0, #, #[[1]]], Product[Prime@ i, {i, Length@ w}]] &@ Reap[Do[If[# < lim, Sow[#]; k = 1, If[k >= Length@ w, Break[], k++]] &@ Apply[Times, MapIndexed[Prime[First@ #2]^#1 &, #]] &@ Set[w, If[k == 1, MapAt[# + 1 &, w, k], PadLeft[#, Length@ w, First@ #] &@ Drop[MapAt[# + Boole[i > 1] &, w, k], k - 1]]], {i, Infinity}]][[-1]] ] &, ww]]; Map[(1 + If[# == 1, 1, Apply[Times, NextPrime[#1]^#2 & @@@ FactorInteger[#]]])/2 &@ Apply[Times, Prime@ Table[LengthWhile[#1, # >= j &], {j, #2}] & @@ {#, Max[#]} &@ If[# == 1, {0}, Function[f, ReplacePart[ConstantArray[0, PrimePi@ f[[-1, 1]] ], #] &@ Map[PrimePi@ First@ # -> Last@ # &, f]]@ FactorInteger@ #]] &, Union@ Flatten@ a025487@ 5] (* Michael De Vlieger, Feb 11 2021 *)
  • PARI
    A341351(n) = A048673(A181815(n));

Formula

a(n) = A048673(A181815(n)).
For all n >= 1, A181812(a(n)) = A025487(n).

A359164 Difference between Kimberling's paraphrases and its Möbius transform.

Original entry on oeis.org

0, 1, 1, 1, 1, 2, 1, 1, 2, 3, 1, 2, 1, 4, 4, 1, 1, 5, 1, 3, 5, 6, 1, 2, 3, 7, 5, 4, 1, 8, 1, 1, 7, 9, 6, 5, 1, 10, 8, 3, 1, 11, 1, 6, 11, 12, 1, 2, 4, 13, 10, 7, 1, 14, 8, 4, 11, 15, 1, 8, 1, 16, 14, 1, 9, 17, 1, 9, 13, 18, 1, 5, 1, 19, 18, 10, 9, 20, 1, 3, 14, 21, 1, 11, 11, 22, 16, 6, 1, 23, 10, 12, 17, 24, 12
Offset: 1

Views

Author

Antti Karttunen, Dec 22 2022

Keywords

Crossrefs

Programs

Formula

a(n) = A003602(n) - A349136(n).
a(n) = Sum_{d|n, dA349136(d).
a(n) = -Sum_{d|n, dA008683(n/d)*A003602(d).
a((2^e)*prime(n)) = A111333(n) for all n >= 1 and e >= 1.
Previous Showing 11-14 of 14 results.