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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A351963 Lexicographically earliest infinite sequence such that a(i) = a(j) => A278222(A109812(i)) = A278222(A109812(j)), for all i, j >= 1.

Original entry on oeis.org

1, 1, 1, 2, 1, 3, 3, 1, 2, 3, 3, 2, 3, 4, 1, 4, 2, 3, 3, 5, 3, 5, 3, 6, 3, 5, 2, 7, 1, 5, 6, 3, 5, 5, 3, 5, 6, 3, 8, 2, 9, 3, 5, 4, 5, 5, 3, 8, 5, 1, 8, 5, 3, 7, 5, 3, 10, 6, 3, 6, 6, 5, 6, 5, 6, 5, 5, 4, 8, 3, 9, 5, 5, 7, 2, 11, 3, 10, 3, 10, 6, 6, 9, 5, 8, 6, 5, 8, 5, 10, 6, 12, 6, 10, 6, 5, 10, 4, 6, 8, 5, 13
Offset: 1

Views

Author

Antti Karttunen, Apr 06 2022

Keywords

Comments

Restricted growth sequence transform of A278222(A109812(n)), or equally of, A278222(A351965(n)).
For all i, j: A351578(i) = A351578(j) => a(i) = a(j) => A352884(i) = A352884(j).

Crossrefs

Programs

  • PARI
    rgs_transform(invec) = { my(om = Map(), outvec = vector(length(invec)), u=1); for(i=1, length(invec), if(mapisdefined(om,invec[i]), my(pp = mapget(om, invec[i])); outvec[i] = outvec[pp] , mapput(om,invec[i],i); outvec[i] = u; u++ )); outvec; };
    v109812 = readvec("b109812_to10e5.txt"); \\ Prepared from b-file data with gawk ' { print $2 } '
    up_to = #v109812;
    A109812(n) = v109812[n];
    A005940(n) = { my(p=2, t=1); n--; until(!n\=2, if((n%2), (t*=p), p=nextprime(p+1))); (t); };
    A046523(n) = { my(f=vecsort(factor(n)[, 2], , 4), p); prod(i=1, #f, (p=nextprime(p+1))^f[i]); }; \\ From A046523
    v351963 = rgs_transform(vector(up_to, n, A046523(A005940(1+A109812(n)))));
    A351963(n) = v351963[n];

A278262 a(n) = A278222(A179016(n)).

Original entry on oeis.org

2, 4, 2, 8, 2, 12, 16, 2, 12, 24, 12, 32, 2, 12, 24, 30, 24, 12, 60, 24, 64, 2, 12, 24, 30, 24, 30, 210, 60, 48, 12, 60, 12, 180, 8, 24, 16, 128, 2, 12, 24, 30, 24, 30, 210, 60, 48, 30, 210, 30, 420, 12, 60, 24, 96, 12, 60, 12, 180, 60, 360, 360, 24, 216, 72, 16, 432, 256, 2, 12, 24, 30, 24, 30, 210, 60, 48, 30, 210, 30, 420, 12, 60, 24, 96, 30, 210, 30, 420
Offset: 1

Views

Author

Antti Karttunen, Nov 22 2016

Keywords

Crossrefs

Cf. also A213712, A278232.

Programs

Formula

a(n) = A278222(A179016(n)).

A286242 Compound filter: a(n) = P(A278222(n), A278219(n)), where P(n,k) is sequence A000027 used as a pairing function.

Original entry on oeis.org

1, 5, 12, 14, 12, 84, 40, 44, 12, 142, 216, 183, 40, 265, 86, 152, 12, 142, 826, 265, 216, 1860, 607, 489, 40, 832, 607, 1117, 86, 619, 226, 560, 12, 142, 826, 265, 826, 5080, 2497, 619, 216, 2956, 4308, 4155, 607, 8575, 1105, 1533, 40, 832, 2497, 2116, 607, 5731, 4501, 3475, 86, 1402, 1105, 3475, 226, 1759, 698, 2144, 12, 142, 826, 265, 826, 5080, 2497, 619, 826
Offset: 0

Views

Author

Antti Karttunen, May 07 2017

Keywords

Crossrefs

Programs

  • PARI
    A003188(n) = bitxor(n, n>>1);
    A005940(n) = { my(p=2, t=1); n--; until(!n\=2, if((n%2), (t*=p), p=nextprime(p+1))); t }; \\ Modified from code of M. F. Hasler
    A046523(n) = { my(f=vecsort(factor(n)[, 2], , 4), p); prod(i=1, #f, (p=nextprime(p+1))^f[i]); };  \\ This function from Charles R Greathouse IV, Aug 17 2011
    A278222(n) = A046523(A005940(1+n));
    A278219(n) = A278222(A003188(n));
    A286242(n) = (2 + ((A278222(n)+A278219(n))^2) - A278222(n) - 3*A278219(n))/2;
    for(n=0, 16383, write("b286242.txt", n, " ", A286242(n)));
    
  • Python
    from sympy import prime, factorint
    import math
    def T(n, m): return ((n + m)**2 - n - 3*m + 2)/2
    def A(n): return n - 2**int(math.floor(math.log(n, 2)))
    def b(n): return n + 1 if n<2 else prime(1 + (len(bin(n)[2:]) - bin(n)[2:].count("1"))) * b(A(n))
    def a005940(n): return b(n - 1)
    def P(n):
        f=factorint(n)
        return sorted([f[i] for i in f])
    def a046523(n):
        x=1
        while True:
            if P(n) == P(x): return x
            else: x+=1
    def a003188(n): return n^(n>>1)
    def a243353(n): return a005940(1 + a003188(n))
    def a278219(n): return a046523(a243353(n))
    def a278222(n): return a046523(a005940(n + 1))
    def a(n): return T(a278222(n), a278219(n)) # Indranil Ghosh, May 07 2017
  • Scheme
    (define (A286242 n) (* (/ 1 2) (+ (expt (+ (A278222 n) (A278219 n)) 2) (- (A278222 n)) (- (* 3 (A278219 n))) 2)))
    

Formula

a(n) = (1/2)*(2 + ((A278222(n)+A278219(n))^2) - A278222(n) - 3*A278219(n)).
a(n) = (1/2)*(2 + ((A278222(n)+A278222(A003188(n)))^2) - A278222(n) - 3*A278222(A003188(n))).

A286374 a(n) = A278222(n^2).

Original entry on oeis.org

1, 2, 2, 6, 2, 12, 6, 12, 2, 30, 12, 48, 6, 210, 12, 24, 2, 30, 30, 420, 12, 360, 48, 30, 6, 120, 210, 1260, 12, 420, 24, 48, 2, 30, 30, 420, 30, 4620, 420, 480, 12, 420, 360, 1080, 48, 960, 30, 210, 6, 420, 120, 2310, 210, 3360, 1260, 1680, 12, 1260, 420, 6300, 24, 840, 48, 96, 2, 30, 30, 420, 30, 4620, 420, 2520, 30, 4620, 4620, 6720, 420, 9240, 480, 180
Offset: 0

Views

Author

Antti Karttunen, May 09 2017

Keywords

Crossrefs

Cf. A159918 (one of the matched sequences).

Programs

  • Python
    from sympy import prime, factorint
    import math
    def A(n): return n - 2**int(math.floor(math.log(n, 2)))
    def b(n): return n + 1 if n<2 else prime(1 + (len(bin(n)[2:]) - bin(n)[2:].count("1"))) * b(A(n))
    def a005940(n): return b(n - 1)
    def P(n):
        f = factorint(n)
        return sorted([f[i] for i in f])
    def a046523(n):
        x=1
        while True:
            if P(n) == P(x): return x
            else: x+=1
    def a278222(n): return a046523(a005940(n + 1))
    def a(n): return a278222(n**2) # Indranil Ghosh, May 09 2017
  • Scheme
    (define (A286374 n) (A278222 (* n n)))
    

Formula

a(n) = A278222(A000290(n)) = A278222(n^2).

A286375 a(n) = A278222(n^3).

Original entry on oeis.org

1, 2, 2, 36, 2, 96, 36, 840, 2, 1260, 96, 1260, 36, 2310, 840, 5040, 2, 1260, 1260, 69300, 96, 4620, 1260, 4320, 36, 1680, 2310, 12600, 840, 36960, 5040, 30240, 2, 1260, 1260, 831600, 1260, 415800, 69300, 2646000, 96, 27720, 4620, 900900, 1260, 221760, 4320, 277200, 36, 83160, 1680, 13860, 2310, 180180, 12600, 166320, 840, 15315300, 36960, 13860, 5040
Offset: 0

Views

Author

Antti Karttunen, May 09 2017

Keywords

Crossrefs

Cf. A192085 (one of the matched sequences).

Programs

Formula

a(n) = A278222(A000578(n)) = A278222(n^3).

A286376 a(n) = A278222(A277699(n)).

Original entry on oeis.org

2, 2, 6, 2, 24, 6, 12, 2, 60, 24, 180, 6, 120, 12, 24, 2, 60, 60, 420, 24, 180, 180, 60, 6, 192, 120, 384, 12, 240, 24, 48, 2, 60, 60, 420, 60, 720, 420, 360, 24, 420, 180, 1260, 180, 4620, 60, 420, 6, 720, 192, 5040, 120, 5040, 384, 1680, 12, 1440, 240, 4320, 24, 480, 48, 96, 2, 60, 60, 420, 60, 2520, 420, 1260, 60, 420, 720, 1260, 420, 1260, 360, 180, 24
Offset: 1

Views

Author

Antti Karttunen, May 09 2017

Keywords

Crossrefs

Programs

Formula

a(n) = A278222(A277699(n)).

A286464 Compound filter (3-adic valuation & signature for base-2 1-runs): a(n) = P(A051064(n), A278222(n)), where P(n,k) is sequence A000027 used as a pairing function.

Original entry on oeis.org

2, 2, 12, 2, 16, 12, 29, 2, 31, 16, 67, 12, 67, 29, 138, 2, 16, 31, 67, 16, 467, 67, 277, 12, 67, 67, 745, 29, 277, 138, 497, 2, 23, 16, 67, 31, 436, 67, 302, 16, 436, 467, 1771, 67, 1894, 277, 1129, 12, 67, 67, 668, 67, 1771, 745, 2557, 29, 302, 277, 2557, 138, 1129, 497, 2148, 2, 16, 23, 67, 16, 467, 67, 277, 31, 436, 436, 1832, 67, 1771, 302, 1129, 16, 566
Offset: 1

Views

Author

Antti Karttunen, May 10 2017

Keywords

Crossrefs

Programs

Formula

a(n) = (1/2)*(2 + ((A051064(n)+A278222(n))^2) - A051064(n) - 3*A278222(n)).

A286538 a(n) = A278222(A267111(n)).

Original entry on oeis.org

2, 2, 4, 2, 6, 8, 4, 2, 6, 12, 16, 6, 12, 8, 4, 2, 6, 12, 24, 32, 6, 30, 36, 12, 24, 16, 6, 12, 12, 8, 4, 2, 6, 12, 24, 48, 64, 6, 30, 60, 72, 12, 60, 72, 24, 48, 32, 6, 30, 36, 30, 60, 36, 12, 24, 24, 16, 6, 12, 12, 12, 8, 4, 2, 6, 12, 24, 48, 96, 128, 6, 30, 60, 120, 144, 12, 60, 180, 216, 24, 120, 144, 48, 96, 64, 6
Offset: 1

Views

Author

Antti Karttunen, May 17 2017

Keywords

Crossrefs

Cf. A267111, A278222, A286536, A286539 (rgs-version of this sequence).

Programs

Formula

a(n) = A278222(A267111(n)).

A286552 Ordinal transform of A286622, or equally, of A278222.

Original entry on oeis.org

1, 1, 2, 1, 3, 1, 2, 1, 4, 2, 3, 1, 3, 2, 2, 1, 5, 4, 5, 3, 6, 1, 4, 1, 4, 5, 6, 1, 3, 2, 2, 1, 6, 7, 8, 7, 9, 2, 8, 3, 10, 3, 4, 1, 9, 2, 4, 1, 5, 10, 11, 2, 12, 3, 3, 1, 4, 5, 6, 2, 3, 2, 2, 1, 7, 11, 12, 13, 13, 5, 14, 7, 14, 6, 7, 4, 15, 5, 8, 3, 15, 8, 9, 6, 10, 1, 7, 1, 16, 8, 9, 1, 9, 2, 4, 1, 6, 17, 18, 4, 19, 10, 5, 3, 20, 11, 12, 2, 6, 3, 4, 1, 5
Offset: 0

Views

Author

Antti Karttunen, May 21 2017

Keywords

Crossrefs

A286601 a(n) = A278222(A193231(n)).

Original entry on oeis.org

1, 2, 4, 2, 6, 2, 4, 8, 16, 8, 4, 12, 6, 12, 6, 2, 6, 2, 6, 12, 6, 30, 24, 12, 16, 32, 24, 8, 36, 12, 4, 12, 36, 12, 4, 12, 36, 72, 60, 12, 16, 48, 64, 32, 24, 8, 24, 72, 6, 12, 6, 2, 24, 12, 6, 30, 60, 12, 24, 48, 6, 30, 60, 30, 210, 30, 60, 120, 6, 30, 60, 30, 60, 180, 60, 12, 96, 48, 24, 120, 6, 30, 24, 12, 6, 2, 6, 12, 60, 30, 6, 30
Offset: 0

Views

Author

Antti Karttunen, Jun 04 2017

Keywords

Crossrefs

Cf. A193231, A234022, A278222, A278231, A278233, A286602 (rgs-version of this sequence).

Programs

Formula

a(n) = A278222(A193231(n)).
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