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.

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A323178 a(n) = 1 + 100*n^2 for n >= 0.

Original entry on oeis.org

1, 101, 401, 901, 1601, 2501, 3601, 4901, 6401, 8101, 10001, 12101, 14401, 16901, 19601, 22501, 25601, 28901, 32401, 36101, 40001, 44101, 48401, 52901, 57601, 62501, 67601, 72901, 78401, 84101, 90001, 96101, 102401, 108901
Offset: 0

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Author

Paul Curtz, Jan 06 2019

Keywords

Comments

Terms of A261327 ending in 1 (01 for n > 0.)
a(n) mod 9 = period 9: repeat [1, 2, 5, 1, 8, 8, 1, 5, 2] = A275704(n+3).
(Analogous sequence: b(n) = 29 + 100*n*(n+1) = A261327(A017329) = 29, 229, 629, ... .)

Crossrefs

Subsequence of A017281.

Programs

  • Mathematica
    a[n_] := 1 + 100*n^2 ; Array[a, 50, 0] (* or *)
    CoefficientList[Series[(-1 - 98 x - 101 x^2)/(-1 + x)^3, {x, 0, 50}], x] (* or *)
    CoefficientList[Series[E^x (1 + 100 x + 100 x^2), {x, 0, 50}], x]*Table[n!, {n, 0, 50}] (* Stefano Spezia, Jan 06 2019 *)

Formula

a(n) = A261327(A008602(n)).
Recurrence: a(n) = 3*a(n-1) - 3*a(n-2) + a(n-3) for n > 2 with initial values a(0) = 1, a(1) = 101 and a(2) = 401.
From Stefano Spezia, Jan 06 2019: (Start)
O.g.f.: (-1 - 98*x - 101*x^2)/(-1 + x)^3.
E.g.f.: exp(x)*(1 + 100*x + 100*x^2).
(End)

Extensions

Corrected and extended (recurrence formula) by Werner Schulte, Feb 18 2019
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