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 11-20 of 23 results. Next

A233275 Permutation of nonnegative integers obtained by entangling complementary pair A005187 & A055938 with even and odd numbers.

Original entry on oeis.org

0, 1, 3, 2, 6, 7, 5, 4, 12, 13, 14, 10, 15, 11, 9, 8, 24, 25, 26, 28, 27, 29, 20, 30, 21, 22, 18, 31, 23, 19, 17, 16, 48, 49, 50, 52, 51, 53, 56, 54, 57, 58, 40, 55, 59, 41, 60, 42, 61, 44, 36, 43, 45, 62, 46, 37, 38, 34, 63, 47, 39, 35, 33, 32, 96, 97, 98, 100
Offset: 0

Views

Author

Antti Karttunen, Dec 18 2013

Keywords

Comments

It seems that for all n, a(A000079(n)) = A003945(n).

Crossrefs

Inverse permutation: A233276.
Similarly constructed permutation pairs: A135141/A227413, A232751/A232752, A233277/A233278, A233279/A233280, A003188/A006068.

Formula

a(0)=0, a(1)=1, and thereafter, if A079559(n)=1, a(n) = 2*a(A213714(n)-1), else a(n) = 1+(2*a(A234017(n))).
a(n) = A054429(A233277(n)). [Follows from the definitions of these sequences]

A234017 Inverse function for injection A055938.

Original entry on oeis.org

0, 0, 1, 0, 0, 2, 3, 0, 0, 4, 0, 0, 5, 6, 7, 0, 0, 8, 0, 0, 9, 10, 0, 0, 11, 0, 0, 12, 13, 14, 15, 0, 0, 16, 0, 0, 17, 18, 0, 0, 19, 0, 0, 20, 21, 22, 0, 0, 23, 0, 0, 24, 25, 0, 0, 26, 0, 0, 27, 28, 29, 30, 31, 0, 0, 32, 0, 0, 33, 34, 0, 0, 35, 0, 0, 36, 37, 38
Offset: 0

Views

Author

Antti Karttunen, Dec 18 2013

Keywords

Comments

a(0)=0; thereafter if n occurs as a term of A055938, a(n)=its position in A055938, otherwise zero. This works as an "inverse" function for A055938 in a sense that a(A055938(n)) = n for all n.
a(n)*A213714(n) = 0 for all n.

Crossrefs

Programs

Formula

a(n) = (1-A079559(n)) * A234016(n).

A213723 a(n) = smallest natural number x such that x=n+A000120(x), otherwise zero.

Original entry on oeis.org

0, 2, 0, 4, 6, 0, 0, 8, 10, 0, 12, 14, 0, 0, 0, 16, 18, 0, 20, 22, 0, 0, 24, 26, 0, 28, 30, 0, 0, 0, 0, 32, 34, 0, 36, 38, 0, 0, 40, 42, 0, 44, 46, 0, 0, 0, 48, 50, 0, 52, 54, 0, 0, 56, 58, 0, 60, 62, 0, 0, 0, 0, 0, 64, 66, 0, 68, 70, 0, 0, 72, 74, 0, 76, 78
Offset: 0

Views

Author

Antti Karttunen, Nov 01 2012

Keywords

Examples

			a(1) = 2, as 2 is the smallest natural number such that x such that x=1+A000120(x) (as 2=1+A000120(2)=1+1).
a(2) = 0, as there are no solutions for 2, because it belongs to A055938.
a(11) = 14, as 14 is the smallest natural number x such that x=11+A000120(x) (as 14=11+A000120(14)=11+3).
		

Crossrefs

a(A055938(n)) = 0. a(A005187(n)) = A005843(n) = 2n.
Cf. A213724. Used for computing A213725-A213727. Cf. A179016.

Programs

Formula

a(n) = 2*A213714(n).
Also, by partitioning into sums of distinct nonzero terms of A000225: if n can be formed as a sum of (2^a)-1 + (2^b)-1 + (2^c)-1, etc. where the exponents a, b, c are distinct and all > 0, then a(n) = 2^a + 2^b + 2^c, etc. If this is not possible, then n is one of the terms of A055938, and a(n)=0.

A233277 Permutation of nonnegative integers obtained by entangling complementary pair A005187 & A055938 with odd and even numbers.

Original entry on oeis.org

0, 1, 2, 3, 5, 4, 6, 7, 11, 10, 9, 13, 8, 12, 14, 15, 23, 22, 21, 19, 20, 18, 27, 17, 26, 25, 29, 16, 24, 28, 30, 31, 47, 46, 45, 43, 44, 42, 39, 41, 38, 37, 55, 40, 36, 54, 35, 53, 34, 51, 59, 52, 50, 33, 49, 58, 57, 61, 32, 48, 56, 60, 62, 63, 95, 94, 93, 91
Offset: 0

Views

Author

Antti Karttunen, Dec 18 2013

Keywords

Crossrefs

Inverse permutation: A233278.
Similarly constructed permutation pairs: A135141/A227413, A232751/A232752, A233275/A233276, A233279/A233280, A003188/A006068.

Formula

a(0)=0, a(1)=1, and thereafter, if A079559(n)=0, a(n) = 2*a(A234017(n)), else a(n) = 1+(2*a(A213714(n)-1)).
a(n) = A054429(A233275(n)). [Follows from the definitions of these sequences]

A213710 Number of steps to reach 0 when starting from 2^n and iterating the map x -> x - (number of 1's in binary representation of x): a(n) = A071542(2^n) = A218600(n)+1.

Original entry on oeis.org

1, 2, 3, 5, 8, 13, 22, 39, 69, 123, 221, 400, 730, 1344, 2494, 4656, 8728, 16406, 30902, 58320, 110299, 209099, 397408, 757297, 1446946, 2771952, 5323983, 10250572, 19780123, 38243221, 74058514, 143592685, 278661809, 541110612, 1051158028, 2042539461, 3969857206
Offset: 0

Views

Author

Antti Karttunen, Oct 26 2012

Keywords

Comments

Conjecture: A179016(a(n))= 2^n for all n apart from n=2. This is true if all powers of 2 except 2 itself occur in A179016 as in that case they must occur at positions given by this sequence.
This is easy to prove: It suffices to note that after 3 no integer of form (2^k)+1 can occur in A005187, thus for all k >= 2, A213725((2^k)+1) = 1 or equally: A213714((2^k)+1) = 0. - Antti Karttunen, Jun 12 2013

Crossrefs

One more than A218600, which is the partial sums of A213709, thus the latter also gives the first differences of this sequence.
Analogous sequences: A219665, A255062.

Formula

a(n) = A071542(A000079(n)) = A071542(2^n).
a(n) = 1 + A218600(n).

Extensions

a(29)-a(36) from Alois P. Heinz, Jul 03 2022

A255559 One-based column index of n in array A255555.

Original entry on oeis.org

1, 1, 2, 2, 1, 1, 3, 3, 1, 2, 2, 1, 1, 1, 4, 4, 1, 2, 3, 1, 1, 3, 2, 1, 2, 2, 1, 1, 1, 1, 5, 5, 1, 2, 3, 1, 1, 4, 2, 1, 2, 4, 1, 1, 1, 3, 2, 1, 3, 3, 1, 1, 2, 2, 1, 2, 2, 1, 1, 1, 1, 1, 6, 6, 1, 2, 3, 1, 1, 4, 2, 1, 2, 5, 1, 1, 1, 3, 2, 1, 3, 5, 1, 1, 2, 2, 1, 2, 4, 1, 1, 1, 1, 3, 2, 1, 4, 4, 1, 1, 2, 2, 1, 3, 3, 1
Offset: 1

Views

Author

Antti Karttunen, Apr 14 2015

Keywords

Comments

Equally: One-based row index of n in array A255557.

Crossrefs

Cf. also A255560 (corresponding row index).

Formula

a(1) = 1; for n > 1, if A213714(n) = 0 [i.e., if n is one of the terms of A055938], then a(n) = 1, otherwise 1 + a(A213714(n)-1).
In other words, a(1) = 1, and for n > 1, if n = A005187(k) for some k, then a(n) = 1 + a(k-1), otherwise it must be that n is in A055938, in which case a(n) = 1.
Other identities and observations. For all n >= 1:
a(n) <= A256478(n) <= A070939(n).
a(n) <= A256993(n) + 1.

A256989 One-based column index of n in array A256995.

Original entry on oeis.org

0, 1, 2, 3, 1, 1, 4, 2, 1, 2, 5, 1, 1, 1, 3, 2, 1, 3, 6, 1, 1, 2, 2, 1, 2, 4, 1, 1, 1, 1, 3, 2, 1, 4, 7, 1, 1, 2, 2, 1, 3, 3, 1, 1, 1, 2, 3, 1, 5, 2, 1, 1, 2, 2, 1, 2, 4, 1, 1, 1, 1, 1, 3, 2, 1, 5, 8, 1, 1, 2, 2, 1, 3, 3, 1, 1, 1, 2, 4, 1, 4, 2, 1, 1, 2, 2, 1, 3, 4, 1, 1, 1, 1, 2, 6, 1, 3, 2, 1, 1, 2, 3, 1, 3, 2, 1, 1, 1, 3, 5, 1, 2, 2, 1, 1, 2, 2, 1, 2, 4
Offset: 1

Views

Author

Antti Karttunen, Apr 14 2015

Keywords

Comments

Also one-based row index for array A256997.
a(1) = 0 by convention, as 1 is outside of the actual arrays A256995 & A256997.

Crossrefs

Cf. A256990 (corresponding row index), A255559.

Formula

a(1) = 0; for n > 1, if A213714(n) = 0 [i.e., if n is one of the terms of A055938], then a(n) = 1, otherwise a(n) = 1 + a(A213714(n)).
In other words, a(1) = 0, and for n > 1, if n = A005187(k) for some k, then a(n) = 1 + a(k), otherwise it must be that n is in A055938, in which case a(n) = 1.
Other observations. For all n >= 1 it holds that:
a(n) <= A256993(n).

A230414 Inverse function for injection A219650.

Original entry on oeis.org

0, 1, 2, 0, 0, 3, 4, 5, 0, 0, 6, 7, 8, 0, 0, 9, 10, 11, 0, 0, 0, 0, 0, 12, 13, 14, 0, 0, 15, 16, 17, 0, 0, 18, 19, 20, 0, 0, 21, 22, 23, 0, 0, 0, 0, 0, 24, 25, 26, 0, 0, 27, 28, 29, 0, 0, 30, 31, 32, 0, 0, 33, 34, 35, 0, 0, 0, 0, 0, 36, 37, 38, 0, 0, 39, 40, 41
Offset: 0

Views

Author

Antti Karttunen, Oct 31 2013

Keywords

Comments

a(0)=0; thereafter if n occurs as a term of A219650, a(n)=its position in A219650, otherwise zero. This works as an "inverse" function for A219650 in a sense that a(A219650(n)) = n for all n.

Crossrefs

Cf. A219650, A230423, A230424. A219658 gives the positions of zeros after the first one. Analogous sequence for binary system: A213714.

Programs

Formula

a(n) = A230412(n) * A230413(n).
a(n) = A230423(n)/2.

A255560 One-based row index of n in array A255555.

Original entry on oeis.org

1, 2, 1, 2, 3, 4, 1, 2, 5, 3, 4, 6, 7, 8, 1, 2, 9, 5, 3, 10, 11, 4, 6, 12, 7, 8, 13, 14, 15, 16, 1, 2, 17, 9, 5, 18, 19, 3, 10, 20, 11, 4, 21, 22, 23, 6, 12, 24, 7, 8, 25, 26, 13, 14, 27, 15, 16, 28, 29, 30, 31, 32, 1, 2, 33, 17, 9, 34, 35, 5, 18, 36, 19, 3, 37, 38, 39, 10, 20, 40, 11, 4, 41, 42, 21, 22, 43, 23, 6
Offset: 1

Views

Author

Antti Karttunen, Apr 14 2015

Keywords

Comments

Equally: One-based column index of n in array A255557.

Crossrefs

Cf. also A255559 (corresponding column index).

Formula

a(1) = 1; for n > 1, if A213714(n) = 0 [i.e., if n is one of the terms of A055938], then a(n) = 1+A234017(n), otherwise a(n) = a(A213714(n)-1).
In other words, a(1) = 1, and for n > 1, if n = A055938(k) for some k, then a(n) = k+1, otherwise it must be that n = A005187(h) for some h, in which case a(n) = a(h-1).

A256990 One-based row index of n in array A256995.

Original entry on oeis.org

0, 1, 1, 1, 2, 3, 1, 2, 4, 3, 1, 5, 6, 7, 2, 4, 8, 3, 1, 9, 10, 5, 6, 11, 7, 2, 12, 13, 14, 15, 4, 8, 16, 3, 1, 17, 18, 9, 10, 19, 5, 6, 20, 21, 22, 11, 7, 23, 2, 12, 24, 25, 13, 14, 26, 15, 4, 27, 28, 29, 30, 31, 8, 16, 32, 3, 1, 33, 34, 17, 18, 35, 9, 10, 36, 37, 38, 19, 5, 39, 6, 20, 40, 41, 21, 22, 42, 11, 7
Offset: 1

Views

Author

Antti Karttunen, Apr 14 2015

Keywords

Comments

Also one-based column index for array A256997.
a(1) = 0 by convention, as 1 is outside of the actual arrays A256995 & A256997.

Crossrefs

Cf. A256989 (corresponding column index), A255560.

Formula

a(1) = 0; for n > 1, if A213714(n) = 0 [i.e., if n is one of the terms of A055938], then a(n) = A234017(n), otherwise a(n) = a(A213714(n)).
In other words, a(1) = 0, and for n > 1, if n = A055938(k) for some k, then a(n) = k, otherwise it must be that n = A005187(h) for some h, in which case a(n) = a(h).
Previous Showing 11-20 of 23 results. Next