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 1-4 of 4 results.

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

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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

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

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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.

A227547 a(n) = a(n-1) + prime(n-1), with a(1)=3.

Original entry on oeis.org

3, 5, 8, 13, 20, 31, 44, 61, 80, 103, 132, 163, 200, 241, 284, 331, 384, 443, 504, 571, 642, 715, 794, 877, 966, 1063, 1164, 1267, 1374, 1483, 1596, 1723, 1854, 1991, 2130, 2279, 2430, 2587, 2750, 2917, 3090, 3269, 3450, 3641, 3834, 4031, 4230, 4441, 4664
Offset: 1

Views

Author

Vincenzo Librandi, Jul 27 2013

Keywords

Crossrefs

Programs

  • Magma
    [IsOne(n) select 3 else Self(n-1)+NthPrime(n-1): n in [1..50]]; // Bruno Berselli, Jul 30 2013
  • Mathematica
    Accumulate[Join[{3}, Prime[Range[60]]]]

Formula

a(n) = A036439(n) + 1 = A014284(n) + 2 = A007504(n-1) + 3 (in this case, n>1).

A262392 a(n) = A007504(n) + A010693(n).

Original entry on oeis.org

2, 5, 7, 13, 19, 31, 43, 61, 79, 103, 131, 163, 199, 241, 283, 331, 383, 443, 503, 571, 641, 715, 793, 877, 965, 1063, 1163, 1267, 1373, 1483, 1595, 1723, 1853, 1991, 2129, 2279, 2429, 2587, 2749, 2917, 3089, 3269, 3449, 3641, 3833, 4031, 4229
Offset: 0

Views

Author

Altug Alkan, Sep 21 2015

Keywords

Comments

Sequence is interesting because of the fact that a(n) is a prime number for n = 0..20.
Main inspiration of sequence was indices of prime numbers in A036439 and A227547.

Examples

			a(0) = A007504(0) + A010693(0) = 0 + 2 = 2.
a(1) = A007504(1) + A010693(1) = 2 + 3 = 5.
a(2) = A007504(2) + A010693(2) = 5 + 2 = 7.
a(3) = A007504(3) + A010693(3) = 10 + 3 = 13.
a(4) = A007504(4) + A010693(4) = 17 + 2 = 19.
a(5) = A007504(5) + A010693(5) = 28 + 3 = 31.
		

Crossrefs

Programs

  • Mathematica
    s = Accumulate@ Prime@ Range@ 1200; {2}~Join~Table[s[[n]] + If[OddQ@ n, 3, 2], {n, 46}] (* Michael De Vlieger, Sep 21 2015 *)
  • PARI
    a(n) = sum(k=1, n, prime(k)) + (n%2) + 2;
    vector(50, n, a(n-1))

Formula

a(n) = Sum_{k=1..n} prime(k) + n mod 2 + 2 for n>0, a(0)=2 (from Pari code).
Showing 1-4 of 4 results.