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.

Showing 1-5 of 5 results.

A081745 a(n) = A080901(n) - n.

Original entry on oeis.org

1, -2, 2, 6, 3, 7, 11, 8, 12, 9, 13, 17, 14, 18, 22, 19, 23, 20, 17, 21, 18, 22, 26, 23, 27, 31, 28, 32, 29, 33, 37, 34, 38, 42, 39, 36, 33, 30, 27, 24, 21, 25, 29, 26, 30, 34, 31, 35, 32, 36, 40, 37, 41, 45, 42, 46, 43, 40, 44, 41, 45, 42, 39, 36, 40, 37, 34, 31
Offset: 1

Views

Author

N. J. A. Sloane, Apr 08 2003

Keywords

Formula

Periodic with period 168.

A080900 a(1)=1; for n>1, a(n)=a(n-1)-2 if n is already in the sequence, a(n)=a(n-1)+5 otherwise.

Original entry on oeis.org

1, 6, 11, 16, 21, 19, 24, 29, 34, 39, 37, 42, 47, 52, 57, 55, 60, 65, 63, 68, 66, 71, 76, 74, 79, 84, 89, 94, 92, 97, 102, 107, 112, 110, 115, 120, 118, 123, 121, 126, 131, 129, 134, 139, 144, 149, 147, 152, 157, 162, 167, 165, 170, 175, 173, 178, 176
Offset: 1

Views

Author

N. J. A. Sloane and Benoit Cloitre, Apr 01 2003

Keywords

Links

Crossrefs

Cf. A080912, A080913, A080904, A080914, A080578, A080919, A080922, A080927.
Cf. A080901 (starting value = 2), A080905 (run lengths of first differences).

Programs

  • Mathematica
    Fold[Append[#1, #1[[-1]] + If[MemberQ[#1, #2], -2, 5]] &, {1}, Range[2, 57]] (* Ivan Neretin, Mar 03 2016 *)
  • PARI
    up_to = 1001;
A080900list(up_to_n) = { my(xs=Map(), v=vector(up_to_n)); mapput(xs,1,1); v[1] = 1; for(n=2,up_to_n, v[n] = v[n-1]+if(mapisdefined(xs,n), -2, +5); mapput(xs,v[n],n)); (v); };
v080900 = A080900list(up_to);
A080900(n) = v080900[n]; \\ Antti Karttunen, Jan 22 2020

Formula

Perhaps this is asymptotic to c_0*n*(1 + c_1/log n + ...), with c_0 near 2 ?

A081746 a(1)=1; for n>1, a(n)=a(n-1)-3 if n is already in the sequence, a(n)=a(n-1)+5 otherwise.

Original entry on oeis.org

1, 6, 11, 16, 21, 18, 23, 28, 33, 38, 35, 40, 45, 50, 55, 52, 57, 54, 59, 64, 61, 66, 63, 68, 73, 78, 83, 80, 85, 90, 95, 100, 97, 102, 99, 104, 109, 106, 111, 108, 113, 118, 123, 128, 125, 130, 135, 140, 145, 142, 147, 144, 149, 146, 143, 148, 145, 150
Offset: 1

Views

Author

Benoit Cloitre, Apr 05 2003

Keywords

Links

Crossrefs

Cf. A081747, A081748, A080578, A080900, A080901, A080939.

Programs

  • Mathematica
    a[n_] := a[n] = If[n == 1, 1, If[MemberQ[Array[a, n-1], n], a[n-1] - 3, a[n-1] + 5]]; Array[a, 58] (* Jean-François Alcover, Oct 05 2018 *)

Formula

a(n) - n is periodic with period 648.

A080939 a(1)=3; for n>1, a(n)=a(n-1)-2 if n is already in the sequence, a(n)=a(n-1)+5 otherwise.

Original entry on oeis.org

3, 8, 6, 11, 16, 14, 19, 17, 22, 27, 25, 30, 35, 33, 38, 36, 34, 39, 37, 42, 47, 45, 50, 55, 53, 58, 56, 61, 66, 64, 69, 74, 72, 70, 68, 66, 64, 62, 60, 65, 70, 68, 73, 78, 76, 81, 79, 84, 89, 87, 92, 97, 95, 100, 98, 96, 101, 99, 104, 102, 100, 98, 103, 101, 99
Offset: 1

Views

Author

N. J. A. Sloane and Benoit Cloitre, Apr 04 2003

Keywords

Links

Crossrefs

Cf. A080578, A080900, A080901.

Formula

a(n)-n (n >= 1) is periodic with period 168.

A080949 a(1)=0; for n>1, a(n)=a(n-1)-2 if n is already in the sequence, a(n)=a(n-1)+5 otherwise.

Original entry on oeis.org

0, 5, 10, 15, 13, 18, 23, 28, 33, 31, 36, 41, 39, 44, 42, 47, 52, 50, 55, 60, 65, 70, 68, 73, 78, 83, 88, 86, 91, 96, 94, 99, 97, 102, 107, 105, 110, 115, 113, 118, 116, 114, 119, 117, 122, 127, 125, 130, 135, 133, 138, 136, 141, 146, 144, 149, 154, 159
Offset: 1

Views

Author

N. J. A. Sloane and Benoit Cloitre, Apr 04 2003

Keywords

Links

Crossrefs

Cf. A080578, A080900, A080901, A080939.
Showing 1-5 of 5 results.

Started in 1964 by Neil J. A. Sloane | Maintained by The OEIS Foundation Inc.

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