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 1-10 of 24 results. Next

A175970 Complement of A051349(n), where A051349(n) = the lexicographically earliest sequence with first differences as increasing sequence of composites A002808(n).

Original entry on oeis.org

2, 3, 4, 6, 7, 8, 9, 10, 12, 13, 14, 15, 16, 17, 18, 20, 21, 22, 23, 24, 25, 26, 27, 29, 30, 31, 32, 33, 34, 35, 36, 37, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 65, 66, 67, 68, 69, 70
Offset: 1

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Author

Jaroslav Krizek, Oct 31 2010

Keywords

Crossrefs

A122998 Decimal expansion of Sum_{n>=1} 1/A051349(n).

Original entry on oeis.org

1, 5, 8, 1, 9, 3, 4, 8, 2, 2, 5, 4, 2, 0
Offset: 1

Views

Author

Pierre CAMI, Oct 28 2006

Keywords

Comments

a(15) is either 3 or 4. - Robert Price, Jul 27 2011

Examples

			1/1 + 1/5 + 1/11 + 1/19 + 1/28 + 1/38 + 1/50 + 1/64 + 1/79 + 1/95 + 1/113 + ... = 1.5819348...
		

Crossrefs

Cf. A051349.

Extensions

Corrected a(9) from 1 to 2; added a(10)-a(14)=2,5,4,2,0, Robert Price, Jul 27 2011

A014284 Partial sums of primes, if 1 is regarded as a prime (as it was until quite recently, see A008578).

Original entry on oeis.org

1, 3, 6, 11, 18, 29, 42, 59, 78, 101, 130, 161, 198, 239, 282, 329, 382, 441, 502, 569, 640, 713, 792, 875, 964, 1061, 1162, 1265, 1372, 1481, 1594, 1721, 1852, 1989, 2128, 2277, 2428, 2585, 2748, 2915, 3088, 3267, 3448, 3639, 3832, 4029
Offset: 1

Views

Author

Deepan Majmudar (dmajmuda(AT)esq.com)

Keywords

Comments

Lexicographically earliest sequence whose first differences are an increasing sequence of primes. Complement of A175969. - Jaroslav Krizek, Oct 31 2010
A175944(a(n)) = A018252(n). - Reinhard Zumkeller, Mar 18 2011
Partial sums of noncomposite numbers (A008578). - Omar E. Pol, Aug 09 2012

Examples

			a(7) = 42 because the first six primes (2, 3, 5, 7, 11, 13) add up to 41, and 1 + 41 = 42.
		

Crossrefs

Cf. A007504.
Equals A036439(n) - 1.
Cf. A008578.

Programs

Formula

a(n) = Sum_{k <= n} [(A158611(k + 1)) * (A000012(n - k + 1))] = Sum_{k <= n} [(A158611(k + 1)) * (A000012(k))] = Sum_{k <= n} [(A008578(k)) * (A000012(n - k + 1))] = Sum_{k <= n} [(A008578(k)) * (A000012(k))] for n, k >= 1. - Jaroslav Krizek, Aug 05 2009
a(n + 1) = A007504(n) + 1. a(n + 1) - a(n) = A000040(n) = n-th primes. - Jaroslav Krizek, Aug 19 2009
a(n) = a(n-1) + prime(n-1), with a(1)=1. - Vincenzo Librandi, Jul 27 2013
G.f: (x*(1+b(x)))/(1-x) = c(x)/(1-x), where b(x) and c(x) are respectively the g.f. of A000040 and A008578. - Mario C. Enriquez, Dec 10 2016

Extensions

Correction for Aug 2009 change of offset in A158611 and A008578 by Jaroslav Krizek, Jan 27 2010

A053767 Sum of first n composite numbers.

Original entry on oeis.org

0, 4, 10, 18, 27, 37, 49, 63, 78, 94, 112, 132, 153, 175, 199, 224, 250, 277, 305, 335, 367, 400, 434, 469, 505, 543, 582, 622, 664, 708, 753, 799, 847, 896, 946, 997, 1049, 1103, 1158, 1214, 1271, 1329, 1389, 1451, 1514, 1578, 1643, 1709, 1777, 1846, 1916, 1988
Offset: 0

Views

Author

G. L. Honaker, Jr., Mar 29 2000

Keywords

Comments

a(A196415(n)) = A036691(A196415(n)) / A141092(n). - Reinhard Zumkeller, Oct 03 2011

Crossrefs

First differences of A023539.

Programs

  • Haskell
    a053767 n = a053767_list !! (n-1)
    a053767_list = scanl1 (+) a002808_list -- Reinhard Zumkeller, Oct 03 2011
    
  • Maple
    A053767 := proc(n)
            add(A002808(i),i=1..n) ;
    end proc: # R. J. Mathar, Oct 03 2011
    ListTools[PartialSums](remove(isprime,[$2..1000])); # Robert Israel, Jan 09 2015
  • Mathematica
    lst={};s=0;Do[If[ !PrimeQ[n], s=s+n;AppendTo[lst, s]], {n, 2, 10^2}];lst (* Vladimir Joseph Stephan Orlovsky, Aug 14 2008 *)
    Accumulate[Complement[Range[2,100],Prime[Range[PrimePi[100]]]]] (* Harvey P. Dale, Dec 28 2010 *)
    Accumulate[Select[Range[2, 100], ! PrimeQ[#] &]]
  • PARI
    lista(nn) = {my(s=0); forcomposite(n=0, nn, print1(s, ", "); s += n;);} \\ Michel Marcus, Jan 09 2015

Formula

a(n) = A000217(A002808(n)) - A034387(A002808(n)) - 1 . - Robert Israel, Jan 09 2015
a(n) = A051349(n+1) - 1. - Michel Marcus, Feb 16 2018

Extensions

a(0)=0 prepended by Max Alekseyev, Feb 10 2018

A175965 Lexicographically earliest sequence with first differences as increasing sequence of noncomposites A008578.

Original entry on oeis.org

1, 2, 4, 7, 12, 19, 30, 43, 60, 79, 102, 131, 162, 199, 240, 283, 330, 383, 442, 503, 570, 641, 714, 793, 876, 965, 1062, 1163, 1266, 1373, 1482, 1595, 1722, 1853, 1990, 2129, 2278, 2429, 2586, 2749, 2916, 3089, 3268, 3449, 3640, 3833, 4030, 4229, 4440, 4663
Offset: 1

Views

Author

Jaroslav Krizek, Oct 31 2010

Keywords

Comments

Complement of A175966.
A175944(a(n)) = A018252(n). - Reinhard Zumkeller, Mar 18 2011

Crossrefs

Programs

  • Haskell
    a175965 n = a175965_list !! n
    a175965_list = scanl (+) 1 a008578_list
    -- Reinhard Zumkeller, Mar 26 2015
  • Mathematica
    FoldList[Plus,1,Join[{1},Prime[Range[50]]]] (* or *) Accumulate[ Join[ {1,1},Prime[Range[50]]]] (* Harvey P. Dale, Sep 28 2016 *)

Formula

a(n) = A036439(n-1) for n > 1.
a(n) - a(n-1) = A008578(n-1) for n > 1.
a(n) = A014284(n-1) + 1 for n > 1.

A175967 Lexicographically earliest sequence with first differences as increasing sequence of nonprimes A018252.

Original entry on oeis.org

1, 2, 6, 12, 20, 29, 39, 51, 65, 80, 96, 114, 134, 155, 177, 201, 226, 252, 279, 307, 337, 369, 402, 436, 471, 507, 545, 584, 624, 666, 710, 755, 801, 849, 898, 948, 999, 1051, 1105, 1160, 1216, 1273, 1331, 1391, 1453, 1516, 1580, 1645, 1711, 1779
Offset: 1

Views

Author

Jaroslav Krizek, Oct 31 2010

Keywords

Comments

Complement of A175968.

Crossrefs

Programs

  • Haskell
    a175967 n = a175967_list !! n
    a175967_list = scanl (+) 1 a018252_list
    -- Reinhard Zumkeller, Mar 26 2015

Formula

a(n) - a(n-1) = A018252(n-1) for n >= 2.

A175966 Complement of A175965(n), where A175965(n) = the lexicographically earliest sequence with first differences as increasing sequence of noncomposites A008578.

Original entry on oeis.org

3, 5, 6, 8, 9, 10, 11, 13, 14, 15, 16, 17, 18, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 80
Offset: 1

Views

Author

Jaroslav Krizek, Oct 31 2010

Keywords

Crossrefs

A175969 Complement of A014284(n), where A014284(n) = the lexicographically earliest sequence with first differences as increasing sequence of primes A000040.

Original entry on oeis.org

2, 4, 5, 7, 8, 9, 10, 12, 13, 14, 15, 16, 17, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70
Offset: 1

Views

Author

Jaroslav Krizek, Oct 31 2010

Keywords

Crossrefs

A175968 Complement of A175967(n), where A175967(n) = the lexicographically earliest sequence with first differences as increasing sequence of nonprimes A018252(n).

Original entry on oeis.org

3, 4, 5, 7, 8, 9, 10, 11, 13, 14, 15, 16, 17, 18, 19, 21, 22, 23, 24, 25, 26, 27, 28, 30, 31, 32, 33, 34, 35, 36, 37, 38, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79
Offset: 1

Views

Author

Jaroslav Krizek, Oct 31 2010

Keywords

Crossrefs

A154587 Numbers that can be expressed both as the sum of first prime numbers and as the sum of first nonprime numbers.

Original entry on oeis.org

0, 5, 28, 71208, 74139, 9260197734, 12374540078, 7574780746329, 11101148723618, 102581905748236, 3325997869054417, 2886018916559052244845, 46437379006448216748610, 120197329614203475099994
Offset: 1

Views

Author

Keywords

Comments

Is this sequence finite?
Intersection of A007504 and A053767 generates A294174. - R. J. Mathar, Jan 17 2009
Heuristically, the sequence is infinite with about 2 sqrt(log x) members up to x. - Charles R Greathouse IV, Aug 14 2013

Examples

			5 = 2+3 = 1+4. 28 = 2+3+5+7+11 = 1+4+6+8+9.
		

Crossrefs

Intersection of A007504 and A051349. - R. J. Mathar, Jan 17 2009

Programs

  • Maple
    P:=proc(q) local a,b,c,d,n; a:=0; b:=0; c:=0; d:=0; print(a);
    for n from 1 to q do b:=nextprime(b); a:=a+b;
    while cPaolo P. Lava, Feb 23 2018
  • Mathematica
    With[{p = Prime@ Range[10^7]}, {0}~Join~Intersection[Accumulate@ p, Accumulate@ Complement[Range@ Max@ p, p]]] (* Michael De Vlieger, Feb 25 2018 *)

Extensions

Corrected definition and a(6)-a(7) from R. J. Mathar, Jan 17 2009
a(8)-a(11) from Donovan Johnson, Feb 19 2009
a(12)-a(14) from Giovanni Resta, Aug 14 2013
Edited and a(1)=0 prepended by Max Alekseyev, Feb 10 2018
Showing 1-10 of 24 results. Next