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 1-3 of 3 results.

A100341 Denominators of the convergents in the continued fraction expansion for the constant given by A100338, where the partial quotients equal A006519 (greatest power of 2 dividing n).

Original entry on oeis.org

1, 2, 3, 14, 17, 48, 65, 568, 633, 1834, 2467, 11702, 14169, 40040, 54209, 907384, 961593, 2830570, 3792163, 17999222, 21791385, 61581992, 83373377, 728569008, 811942385, 2352453778, 3164396163, 15010038430, 18174434593, 51358907616
Offset: 1

Views

Author

Paul D. Hanna, Nov 18 2004

Keywords

Comments

The convergents for the continued fraction of x are given by A100340(n)/A100341(n) and the convergents for the continued fraction of 2*x are given by A100342(n)/A100343(n), where A100342(n)/A100343(n) = 2*A100340(n)/A100341(n) for all n.

Examples

			The constant is x=1.353871128429882374388894084016608124227333416812...
contfrac(x) = [1;2,1,4,1,2,1,8,1,2,1,4,1,2,1,16,...A006519(n),... ].
		

Crossrefs

Programs

  • PARI
    a(n)=if(n==1,1,if(n==2,2,a(n-1)*2^valuation(n,2)+a(n-2)))

Formula

a(1) = 1, a(2) = 2, a(n) = a(n-1)*A006519(n) + a(n-2).

A100342 Numerators of the convergents in the continued fraction expansion for twice the constant given by A100338, where the partial quotients equal A006519 (greatest power of 2 dividing n) interleaved with 2's.

Original entry on oeis.org

2, 3, 8, 19, 46, 65, 176, 769, 1714, 2483, 6680, 15843, 38366, 54209, 146784, 1228481, 2603746, 3832227, 10268200, 24368627, 59005454, 83374081, 225753616, 986388545, 2198530706, 3184919251, 8568369208, 20321657667, 49211684542
Offset: 1

Views

Author

Paul D. Hanna, Nov 18 2004

Keywords

Comments

The convergents for the continued fraction of x are given by A100340(n)/A100341(n) and the convergents for the continued fraction of 2*x are given by A100342(n)/A100343(n), where A100342(n)/A100343(n) = 2*A100340(n)/A100341(n) for all n.

Examples

			The constant is 2*x=2.707742256859764748777788168033216248454666833624237..
contfrac(2*x) = [2;1, 2,2, 2,1, 2,4, 2,1, 2,2, 2,1, 2,8,... 2, A006519(n),... ].
		

Crossrefs

Programs

  • PARI
    {a(n)=if(n==1,2,if(n==2,3,if(n%2==1,2*a(n-1)+a(n-2), a(n-1)*2^valuation(n/2,2)+a(n-2))))}

Formula

a(1) = 2, a(2) = 3; a(2*n) = a(2*n-1)*A006519(n) + a(2*n-2) for n>1, a(2*n-1) = 2*a(2*n-2) + a(2*n-3) for n>1.

A100343 Denominators of the convergents in the continued fraction expansion for twice the constant given by A100338, where the partial quotients equal A006519 (greatest power of 2 dividing n) interleaved with 2's.

Original entry on oeis.org

1, 1, 3, 7, 17, 24, 65, 284, 633, 917, 2467, 5851, 14169, 20020, 54209, 453692, 961593, 1415285, 3792163, 8999611, 21791385, 30790996, 83373377, 364284504, 811942385, 1176226889, 3164396163, 7505019215, 18174434593, 25679453808, 69533342209
Offset: 1

Views

Author

Paul D. Hanna, Nov 18 2004

Keywords

Comments

The convergents for the continued fraction of x are given by A100340(n)/A100341(n) and the convergents for the continued fraction of 2*x are given by A100342(n)/A100343(n), where A100342(n)/A100343(n) = 2*A100340(n)/A100341(n) for all n.

Examples

			The constant is 2*x=2.707742256859764748777788168033216248454666833624237..
contfrac(2*x) = [2;1, 2,2, 2,1, 2,4, 2,1, 2,2, 2,1, 2,8,... 2, A006519(n),... ].
		

Crossrefs

Programs

  • PARI
    {a(n)=if(n==1,1,if(n==2,1,if(n%2==1,2*a(n-1)+a(n-2), a(n-1)*2^valuation(n/2,2)+a(n-2))))}

Formula

a(1) = 1, a(2) = 1; a(2*n) = a(2*n-1)*A006519(n) + a(2*n-2) for n>1, a(2*n-1) = 2*a(2*n-2) + a(2*n-3) for n>1.
Showing 1-3 of 3 results.