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 1-2 of 2 results.

A282282 Remainder when sum of squares of the first n primes is divided by n-th square pyramidal number.

Original entry on oeis.org

0, 3, 10, 27, 43, 13, 106, 7, 131, 87, 322, 177, 675, 137, 546, 1307, 691, 1496, 266, 1307, 2226, 3627, 902, 2487, 5021, 1585, 3446, 5487, 7276, 9245, 3426, 7275, 11887, 2495, 7546, 12203, 111, 5020, 10094, 16023, 22849, 3565, 10462, 16735, 23144, 28889, 2346, 12907, 23619, 33560, 43632, 6555, 14074, 24587
Offset: 1

Views

Author

Altug Alkan, Feb 11 2017

Keywords

Comments

See also graph of this sequence and compare with the graph of A262744.

Examples

			a(3) = 10 because (2^2 + 3^2 + 5^2) mod (1^2 + 2^2 + 3^2) = 10.
		

Crossrefs

Programs

  • Mathematica
    Table[Mod[Total[Prime[Range@ n]^2], Binomial[n + 2, 3] + Binomial[n + 1, 3]], {n, 54}] (* Michael De Vlieger, Feb 11 2017 *)
  • PARI
    a(n) = sum(k=1, n, prime(k)^2) % (n*(n+1)*(2*n+1)/6);

Formula

a(n) = A024450(n) mod A000330(n).

A263559 a(n) = A083186(n) mod A007504(n).

Original entry on oeis.org

1, 3, 9, 2, 11, 26, 51, 3, 17, 39, 73, 119, 175, 237, 307, 8, 49, 88, 151, 220, 295, 380, 479, 584, 705, 848, 999, 1158, 1321, 1486, 1687, 51, 139, 241, 355, 477, 611, 763, 919, 1085, 1253, 1435, 1633, 1839, 2055, 2277, 2519, 2813, 3111, 3413, 3719, 4023, 4341, 4683, 5019
Offset: 1

Views

Author

Altug Alkan, Oct 21 2015

Keywords

Comments

Sequence is interesting because of its graph. a(n)-a(n-1) < 0 at some points such as n=4 and n=8, although usually a(n)-a(n-1) > 0.

Examples

			a(1) = 1 because prime(prime(1)) mod prime(1) = 3 mod 2 = 1.
		

Crossrefs

Programs

  • Mathematica
    Table[Mod[Sum[Prime@ Prime@ k, {k, n}], Sum[Prime@ k, {k, n}]], {n, 55}] (* Michael De Vlieger, Oct 21 2015 *)
  • PARI
    vector(100, n, sum(k=1, n, prime(prime(k))) % sum(k=1, n, prime(k)))
Showing 1-2 of 2 results.