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.

A378260 G.f. satisfies A(x) = A(x^2)/M(x), where M(x) = Sum_{n>=1} mu(n)*x^n and mu(n) = A008683(n), the Moebius function of n.

Original entry on oeis.org

1, 1, 3, 4, 11, 15, 33, 50, 104, 161, 309, 500, 929, 1529, 2757, 4620, 8207, 13874, 24353, 41478, 72327, 123687, 214685, 368232, 637430, 1095201, 1892492, 3255372, 5619323, 9672701, 16685587, 28734098, 49547095, 85347087, 147130261, 253480414, 436911525, 752798677, 1297444411, 2235633198
Offset: 1

Views

Author

Paul D. Hanna, Nov 25 2024

Keywords

Examples

			G.f. A(x) = x + x^2 + 3*x^3 + 4*x^4 + 11*x^5 + 15*x^6 + 33*x^7 + 50*x^8 + 104*x^9 + 161*x^10 + 309*x^11 + 500*x^12 + 929*x^13 + 1529*x^14 + 2757*x^15 + 4620*x^16 + ...
where A(x) = A(x^2)/M(x) with
M(x) = x - x^2 - x^3 - x^5 + x^6 - x^7 + x^10 - x^11 - x^13 + x^14 + x^15 - x^17 - x^19 + x^21 + x^22 - x^23 + x^26 - x^29 - x^30 + ... + mu(n)*x^n + ...
so that x = M(x) + M(x^2) + M(x^3) + M(x^4) + ... + M(x^n) + ...
Thus, because M(x) = A(x^2)/A(x), we have
x = A(x^2)/A(x) + A(x^4)/A(x^2) + A(x^6)/A(x^3) + A(x^8)/A(x^4) + A(x^10)/A(x^5) + A(x^12)/A(x^6) + ... + A(x^(2*n))/A(x^n) + ...
SPECIFIC VALUES.
A(t) = 1000 at t = 0.57983979082390078033201288097053684588681918658...
A(t) = 100 at t = 0.575850800621842491687274688724496083876096493693...
A(t) = 10 at t = 0.5429296775693301210019293351373468274776922745760...
A(t) = 9 at t = 0.53946231343810887800940222774498269502147986174360...
A(t) = 8 at t = 0.53525852440539581430297764508815311813586247192451...
A(t) = 7 at t = 0.53004645173922704662750351997680689150327151199058...
A(t) = 6 at t = 0.52339661111093477495939037490084005628700411644551...
A(t) = 5 at t = 0.51458419720941955692565375903201066787604036604586...
A(t) = 4 at t = 0.50227142127888616541434068019839636042944372636880...
A(t) = 3 at t = 0.48364898724179834772275350279540495722010623952244...
A(t) = 2 at t = 0.45148154417138074188660255689175385165406842883889...
A(t) = 1 at t = 0.37847838037693933849966786108068785599206753365459...
A(1/2) = 3.85113240762543882840278502418639089248043784485031...
  where A(1/2) = A(1/4)/M(1/2)
  with M(1/2) = 0.10201133481781036474303639393182435154361049251029...
A(1/3) = 0.70553754549458547877689262864744328280095059724850...
  where A(1/3) = A(1/9)/M(1/3)
  with M(1/3) = 0.18199538670263388782780010030056557322634498013538...
A(1/4) = 0.39285915746199878617465323026428187937371048080708...
  where A(1/4) = A(1/16)/M(1/4)
  with M(1/4) = 0.17108224791836356794497287128799432329181231331328...
A(1/5) = 0.27550965922396685715103103981428480321441405929553...
  where A(1/5) = A(1/25)/M(1/5)
  with M(1/5) = 0.15173128129604728456076208173747135942418710339130...
A(1/6) = 0.13414853338170816574291660065981488877610508998414...
A(1/9) = 0.12840457842551423371933936516424287719901492174905...
A(1/16) = 0.06721122777391310699668932733909384687045264984777...
A(1/25) = 0.04180343360348984362058625595257513524070610827394...
		

Crossrefs

Programs

  • PARI
    {a(n) = my(A=x, M = sum(m=1,n,moebius(m)*x^m) +x*O(x^n));
    for(i=1,#binary(n), A = subst(A,x,x^2)/M ); polcoef(A,n)}
    for(n=1,40, print1(a(n),", "))

Formula

G.f. A(x) = Sum_{n>=1} a(n)*x^n satisfies the following formulas.
(1) A(x) = A(x^2)/M(x), where M(x) = Sum_{n>=1} mu(n)*x^n.
(2) x = Sum_{n>=1} A(x^(2*n)) / A(x^n).
a(n) ~ c * d^n, where d = 1.723262561763844024160437963573163520188527015264827413326383054228438457576... and c = 0.7859046910881843332272010625259660209978142303560254864659049088867251443... - Vaclav Kotesovec, Nov 30 2024