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 1-7 of 7 results.

A276573 The infinite trunk of least squares beanstalk: The only infinite sequence such that a(0) = 0 and a(n-1) = a(n) - least number of squares (A002828) that sum to a(n).

Original entry on oeis.org

0, 3, 6, 8, 11, 15, 16, 18, 21, 24, 27, 30, 32, 35, 38, 40, 43, 45, 48, 51, 53, 56, 59, 63, 64, 67, 70, 72, 75, 78, 80, 83, 85, 88, 90, 93, 96, 99, 102, 105, 108, 112, 115, 117, 120, 123, 126, 128, 131, 134, 136, 139, 143, 144, 147, 149, 152, 155, 158, 160, 162, 165, 168, 171, 173, 176, 179, 183, 186, 189, 192, 195
Offset: 0

Views

Author

Antti Karttunen, Sep 07 2016

Keywords

Crossrefs

Cf. A002828, A005563, A255131, A260731, A260733, A262689, A276572, A276574, A276575 (first differences), A277016 (squares present), A277015 (their square roots), A277888 (primes), A278486 (numbers one more than a prime), A278265, A278487, A278488, A278491 (another subsequence), A278497, A278498, A278499, A278513, A278516, A278517, A278518, A278519, A278521, A278522.
Cf. A277890 & A277891 (number of even and odd terms in each range. The latter seem to be slightly more numerous), A277889.
Positions of nonzero terms in A278515.
Subsequence of A278489, no common terms with A278490.
Cf. also A179016, A259934, A276583, A276613, A276623 for similar constructions.

Programs

Formula

a(n) = A276574(A276572(n)).
Other identities and observations. For all n >= 0:
A260731(a(n)) = n.
a(A260733(n+1)) = A005563(n).
A278517(n) <= a(n) <= A278519(n).
A010873(a(n)) = A278499(n). [Terms reduced modulo 4.]
A010877(a(n)) = A278488(n). [modulo 8.]
A046523(a(n)) = A278497(n). [Least number with the same prime signature.]
A008683(a(n)) = A278513(n).
A065338(a(n)) = A278498(n).
A278509(a(n)) = A278265(n).
A278216(a(n)) = A278516(n). [Number of children the n-th node of the trunk has.]

Extensions

Definition clarified and more identities added to the Formula section by Antti Karttunen, Nov 28 2016

A260731 a(n) = Number of steps to reach 0 starting from x=n and using the iterated process: x -> x - A002828(x), where A002828(x) = the least number of squares that add up to x.

Original entry on oeis.org

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

Views

Author

Antti Karttunen, Aug 12 2015

Keywords

Crossrefs

Left inverse of A276573, A278517 and A278519. A278518(n) gives the number of times n occurs (run lengths).
Cf. also A261221.

Programs

  • Mathematica
    A002828[n_] := Which[n == 0, 0, SquaresR[1, n] > 0, 1, SquaresR[2, n] > 0, 2, SquaresR[3, n] > 0, 3, True, 4]; a[0] = 0; a[n_] := a[n] = 1 + a[n - A002828[n]]; Table[a[n], {n, 0, 100}] (* Jean-François Alcover, Nov 14 2016 *)

Formula

a(0) = 0; for >= 1, a(n) = 1 + A260731(A255131(n)).
From Antti Karttunen, Nov 28 2016: (Start)
For all n >= 0, a(A278517(n)) = a(A278519(n)) = a(A276573(n)) = n.
(End)

A278517 a(n) = smallest k for which A260731(k) = n.

Original entry on oeis.org

0, 1, 4, 8, 9, 12, 16, 18, 20, 24, 25, 29, 32, 34, 36, 40, 43, 45, 48, 49, 52, 56, 58, 61, 64, 67, 70, 72, 74, 77, 80, 81, 84, 88, 90, 93, 96, 98, 100, 104, 106, 109, 113, 116, 120, 121, 125, 128, 130, 133, 136, 139, 142, 144, 146, 148, 152, 155, 157, 160, 162, 164, 168, 169, 172, 176, 178, 180, 184, 187, 190, 193, 196, 200
Offset: 0

Views

Author

Antti Karttunen, Nov 28 2016

Keywords

Crossrefs

Cf. A260731 (a left inverse), A278518 (first differences), A278519, A278521.
Cf. also A002828, A276573.

Formula

For all n >= 0, A260731(a(n)) = n.

A278519 a(n) = largest k for which A260731(k) = n.

Original entry on oeis.org

0, 3, 7, 8, 11, 15, 17, 19, 23, 24, 28, 31, 33, 35, 39, 42, 44, 47, 48, 51, 55, 57, 60, 63, 66, 69, 71, 73, 76, 79, 80, 83, 87, 89, 92, 95, 97, 99, 103, 105, 108, 112, 115, 119, 120, 124, 127, 129, 132, 135, 138, 141, 143, 145, 147, 151, 154, 156, 159, 161, 163, 167, 168, 171, 175, 177, 179, 183, 186, 189, 192, 195, 199, 201
Offset: 0

Views

Author

Antti Karttunen, Nov 28 2016

Keywords

Crossrefs

Cf. A260731 (a left inverse), A278517, A278518 (first differences, after its initial 1), A278522.

Programs

  • Scheme
    (define (A278519 n) (if (zero? n) n (+ -1 (A278517 (+ 1 n)))))

Formula

a(0) = 0; for n > 0, a(n) = A278517(1+n)-1.
For all n >= 0, A260731(a(n)) = n.

A278521 a(n) = A276573(n) - A278517(n).

Original entry on oeis.org

0, 2, 2, 0, 2, 3, 0, 0, 1, 0, 2, 1, 0, 1, 2, 0, 0, 0, 0, 2, 1, 0, 1, 2, 0, 0, 0, 0, 1, 1, 0, 2, 1, 0, 0, 0, 0, 1, 2, 1, 2, 3, 2, 1, 0, 2, 1, 0, 1, 1, 0, 0, 1, 0, 1, 1, 0, 0, 1, 0, 0, 1, 0, 2, 1, 0, 1, 3, 2, 2, 2, 2, 2, 0, 1, 2, 2, 2, 2, 2, 0, 0, 2, 3, 1, 2, 3, 2, 1, 0, 1, 2, 0, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0, 0, 2, 2, 0, 0, 0, 0, 0, 0, 0, 1, 1, 0, 0, 2, 0, 0
Offset: 0

Views

Author

Antti Karttunen, Nov 28 2016

Keywords

Crossrefs

Programs

Formula

a(n) = A276573(n) - A278517(n).

A278522 a(n) = A278519(n) - A276573(n).

Original entry on oeis.org

0, 0, 1, 0, 0, 0, 1, 1, 2, 0, 1, 1, 1, 0, 1, 2, 1, 2, 0, 0, 2, 1, 1, 0, 2, 2, 1, 1, 1, 1, 0, 0, 2, 1, 2, 2, 1, 0, 1, 0, 0, 0, 0, 2, 0, 1, 1, 1, 1, 1, 2, 2, 0, 1, 0, 2, 2, 1, 1, 1, 1, 2, 0, 0, 2, 1, 0, 0, 0, 0, 0, 0, 1, 1, 1, 0, 0, 0, 0, 1, 2, 0, 0, 0, 0, 0, 0, 0, 2, 1, 1, 0, 2, 1, 2, 2, 1, 1, 1, 1, 2, 2, 2, 1, 0, 0, 1, 1, 2, 2, 1, 2, 2, 1, 1, 1, 2, 0, 1, 2, 1
Offset: 0

Views

Author

Antti Karttunen, Nov 28 2016

Keywords

Comments

First 3 occurs as a(133).

Crossrefs

Programs

Formula

a(n) = A278519(n) - A276573(n).

A278516 Number of children the n-th node (counted from the root 0) has in the infinite trunk of least squares beanstalk tree: a(n) = A278216(A276573(n)).

Original entry on oeis.org

4, 4, 1, 3, 3, 2, 2, 2, 1, 4, 3, 2, 2, 4, 1, 1, 3, 1, 3, 3, 1, 3, 3, 3, 1, 2, 1, 2, 2, 1, 3, 3, 1, 3, 1, 1, 2, 4, 2, 1, 1, 1, 3, 1, 4, 3, 2, 2, 2, 1, 1, 2, 2, 2, 3, 1, 2, 3, 2, 2, 2, 1, 3, 3, 1, 2, 3, 2, 1, 1, 2, 4, 2, 2, 3, 1, 2, 1, 3, 3, 1, 3, 3, 1, 1, 1, 2, 3, 1, 3, 2, 3, 1, 3, 1, 1, 3, 2, 2, 3, 1, 2, 2, 1, 3, 3, 2, 2, 1, 1, 2, 1, 1, 3, 3, 2, 1, 4, 2, 1, 3
Offset: 0

Views

Author

Antti Karttunen, Nov 28 2016

Keywords

Comments

Naturally, all terms must be > 0 and <= 4.

Crossrefs

Programs

Formula

a(n) = A278216(A276573(n)).
Showing 1-7 of 7 results.