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 12 results. Next

A017173 a(n) = 9*n + 1.

Original entry on oeis.org

1, 10, 19, 28, 37, 46, 55, 64, 73, 82, 91, 100, 109, 118, 127, 136, 145, 154, 163, 172, 181, 190, 199, 208, 217, 226, 235, 244, 253, 262, 271, 280, 289, 298, 307, 316, 325, 334, 343, 352, 361, 370, 379, 388, 397, 406, 415, 424, 433, 442, 451, 460, 469, 478
Offset: 0

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Author

Keywords

Comments

Also all the numbers with digital root 1; A010888(a(n)) = 1. - Rick L. Shepherd, Jan 12 2009
A116371(a(n)) = A156144(a(n)); positions where records occur in A156144: A156145(n+1) = A156144(a(n)). - Reinhard Zumkeller, Feb 05 2009
If A=[A147296] 9*n^2+2*n (n>0, 11, 40, 87, ...); Y=[A010701] 3 (3, 3, 3, ...); X=[A017173] 9*n+1 (n>0, 10, 19, 28, ...), we have, for all terms, Pell's equation X^2 - A*Y^2 = 1. Example: 10^2 - 11*3^2 = 1; 19^2 - 40*3^2 = 1; 28^2 - 87*3^2 = 1. - Vincenzo Librandi, Aug 01 2010

Crossrefs

Cf. A093644 ((9,1) Pascal, column m=1).
Numbers with digital root m: this sequence (m=1), A017185 (m=2), A017197 (m=3), A017209 (m=4), A017221 (m=5), A017233 (m=6), A017245 (m=7), A017257 (m=8), A008591 (m=9).

Programs

Formula

G.f.: (1 + 8*x)/(1 - x)^2.
a(n) = 2*a(n-1) - a(n-2) with a(0)=1, a(1)=10. - Vincenzo Librandi, Aug 01 2010
E.g.f.: exp(x)*(1 + 9*x). - Stefano Spezia, Apr 20 2023
a(n) = A016777(3*n). - Elmo R. Oliveira, Apr 12 2025

A114099 Number of partitions of n into parts with digital root = 9.

Original entry on oeis.org

1, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 2, 0, 0, 0, 0, 0, 0, 0, 0, 3, 0, 0, 0, 0, 0, 0, 0, 0, 5, 0, 0, 0, 0, 0, 0, 0, 0, 7, 0, 0, 0, 0, 0, 0, 0, 0, 11, 0, 0, 0, 0, 0, 0, 0, 0, 15, 0, 0, 0, 0, 0, 0, 0, 0, 22, 0, 0, 0, 0, 0, 0, 0, 0, 30, 0, 0, 0, 0, 0, 0, 0, 0, 42, 0, 0, 0, 0, 0, 0, 0, 0, 56, 0, 0, 0
Offset: 0

Views

Author

Reinhard Zumkeller, Feb 12 2006

Keywords

Comments

a(n) = A114102(n) - A116371(n) - A116372(n) - A116373(n) - A116374(n) - A116375(n) - A116376(n) - A116377(n) - A116378(n).

Examples

			a(27) = #{27, 18+9, 9+9+9} = 3.
		

Crossrefs

Programs

Formula

a(n) = A000041(floor(n/9))*0^(n mod 9).
a(9n) = A000041(n) and for all others a(n) = 0. [Robert G. Wilson v, Apr 25 2010]

A114102 Number of partitions of n such that all parts of a partition have the same digital root.

Original entry on oeis.org

1, 2, 2, 3, 2, 4, 2, 4, 3, 4, 3, 7, 4, 5, 7, 6, 5, 8, 5, 8, 11, 8, 7, 16, 9, 10, 13, 12, 10, 22, 11, 15, 23, 16, 16, 26, 16, 18, 32, 22, 21, 41, 24, 27, 40, 28, 26, 55, 30, 36, 59, 40, 38, 65, 41, 45, 77, 48, 51, 95, 57, 60, 97, 66, 63, 119, 68, 80, 131, 89, 85, 150, 91, 96, 166, 104
Offset: 1

Views

Author

Reinhard Zumkeller, Feb 12 2006

Keywords

Comments

a(n) = A116371(n) + A116372(n) + A116373(n) + A116374(n) + A116375(n) + A116376(n) + A116377(n) + A116378(n) + A114099(n).

Examples

			a(10) = #{10, 5+5, 2+2+2+2+2, 10x1} = 4;
a(11) = #{11, 10+1, 11x1} = 3;
a(12) = #{12, 10+1+1, 6+6, 4+4+4, 3+3+3+3, 2+2+2+2+2+2, 12x1} = 7.
		

Crossrefs

Cf. A010888.
A147706. [From Reinhard Zumkeller, Nov 11 2008]
A156144. [From Reinhard Zumkeller, Feb 05 2009]

Programs

  • Haskell
    a114102 n = length $ filter (== 1) $
                map (length . nub . (map a010888)) $ ps 1 n
       where ps x 0 = [[]]
             ps x y = [t:ts | t <- [x..y], ts <- ps t (y - t)]
    -- Reinhard Zumkeller, Feb 04 2014

A116373 Number of partitions of n into parts with digital root = 3.

Original entry on oeis.org

0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 2, 0, 0, 2, 0, 0, 2, 0, 0, 3, 0, 0, 4, 0, 0, 4, 0, 0, 5, 0, 0, 6, 0, 0, 7, 0, 0, 8, 0, 0, 10, 0, 0, 11, 0, 0, 13, 0, 0, 15, 0, 0, 17, 0, 0, 19, 0, 0, 23, 0, 0, 26, 0, 0, 29, 0, 0, 33, 0, 0, 38, 0, 0, 42, 0, 0, 48, 0, 0, 54, 0, 0, 61, 0, 0, 68, 0, 0, 77, 0, 0, 85, 0, 0, 96
Offset: 1

Views

Author

Reinhard Zumkeller, Feb 12 2006

Keywords

Comments

a(n) = A114102(n) - A116371(n) - A116372(n) - A116374(n) - A116375(n) - A116376(n) - A116377(n) - A116378(n) - A114099(n).

Examples

			a(21) = #{21, 12+3+3+3, 3+3+3+3+3+3+3} = 3.
		

Crossrefs

Cf. A010888.
A147706. [From Reinhard Zumkeller, Nov 11 2008]

Formula

a(n) = A035382(floor(n/3))*0^(n mod 3).

A116376 Number of partitions of n into parts with digital root = 6.

Original entry on oeis.org

0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 2, 0, 0, 1, 0, 0, 3, 0, 0, 2, 0, 0, 3, 0, 0, 3, 0, 0, 4, 0, 0, 4, 0, 0, 6, 0, 0, 5, 0, 0, 7, 0, 0, 7, 0, 0, 9, 0, 0, 9, 0, 0, 12, 0, 0, 11, 0, 0, 15, 0, 0, 15, 0, 0, 18, 0, 0, 19, 0, 0, 23, 0, 0, 23, 0, 0, 29, 0, 0, 29, 0, 0, 35, 0, 0, 37
Offset: 1

Views

Author

Reinhard Zumkeller, Feb 12 2006

Keywords

Comments

a(n) = A114102(n) - A116371(n) - A116372(n) - A116373(n) - A116374(n) - A116375(n) - A116377(n) - A116378(n) - A114099(n).

Examples

			a(30) = #{24+6, 15+15, 6+6+6+6+6} = 3.
		

Crossrefs

Cf. A010888.
Cf. A147706.

Programs

  • Maple
    N:= 1000: # to get a(1) to a(N)
    g:= mul(1/(1-x^(6+9*j)), j=0..floor((N-6)/9)):
    S:= series(g, x, N+1):
    seq(coeff(S,x,j),j=1..N); # Robert Israel, Apr 13 2015

Formula

a(n) = A035386(floor(n/3))*0^(n mod 3).
G.f.: Product_{j>=0} 1/(1 - x^(6+9*j)). - Robert Israel, Apr 13 2015

A116372 Number of partitions of n into parts with digital root = 2.

Original entry on oeis.org

0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 1, 3, 1, 3, 1, 3, 1, 3, 2, 3, 3, 3, 4, 3, 4, 3, 4, 4, 4, 6, 4, 7, 4, 8, 4, 8, 5, 8, 7, 8, 9, 8, 10, 8, 11, 9, 11, 12, 11, 15, 11, 17, 11, 18, 12, 19, 15, 19, 19, 19, 22, 19, 24, 20, 25, 24, 26, 29, 26, 34, 26, 37, 27, 39, 31, 40, 38, 41
Offset: 1

Views

Author

Reinhard Zumkeller, Feb 12 2006

Keywords

Comments

a(n) = A114102(n) - A116371(n) - A116373(n) - A116374(n) - A116375(n) - A116376(n) - A116377(n) - A116378(n) - A114099(n).

Examples

			a(31) = #{29+2, 20+11, 11+2+2+2+2+2} = 3.
		

Crossrefs

Cf. A010888.
A147706. [From Reinhard Zumkeller, Nov 11 2008]

A116374 Number of partitions of n into parts with digital root = 4.

Original entry on oeis.org

0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 1, 1, 0, 0, 1, 1, 0, 0, 1, 1, 1, 0, 1, 1, 2, 0, 1, 1, 2, 1, 1, 1, 2, 2, 1, 1, 2, 3, 2, 1, 2, 3, 4, 1, 2, 3, 5, 2, 2, 3, 6, 4, 2, 3, 6, 6, 3, 3, 6, 7, 6, 3, 6, 8, 9, 4, 6, 8, 11, 7, 6, 8, 12, 11, 7, 8, 13, 14, 11, 8, 13, 16, 16, 9, 13, 17, 21, 13, 13, 18, 24, 20, 14, 18, 26
Offset: 1

Views

Author

Reinhard Zumkeller, Feb 12 2006

Keywords

Comments

a(n) = A114102(n) - A116371(n) - A116372(n) - A116373(n) - A116375(n) - A116376(n) - A116377(n) - A116378(n) - A114099(n).

Examples

			a(39) = #{31+4+4, 22+13+4, 13+13+13} = 3.
		

Crossrefs

Cf. A010888.
A147706. [From Reinhard Zumkeller, Nov 11 2008]

A116375 Number of partitions of n into parts with digital root = 5.

Original entry on oeis.org

0, 0, 0, 0, 1, 0, 0, 0, 0, 1, 0, 0, 0, 1, 1, 0, 0, 0, 1, 1, 0, 0, 1, 1, 1, 0, 0, 2, 1, 1, 0, 1, 2, 1, 1, 0, 2, 2, 1, 1, 1, 3, 2, 1, 1, 3, 3, 2, 1, 2, 4, 3, 2, 1, 4, 5, 3, 2, 2, 6, 5, 3, 2, 5, 7, 5, 3, 3, 8, 8, 5, 3, 6, 10, 8, 5, 4, 10, 11, 8, 5, 8, 13, 12, 8, 6, 13, 15, 12, 8, 10, 18, 16, 12, 9, 17, 21, 17
Offset: 1

Views

Author

Reinhard Zumkeller, Feb 12 2006

Keywords

Comments

a(n) = A114102(n) - A116371(n) - A116372(n) - A116373(n) - A116374(n) - A116376(n) - A116377(n) - A116378(n) - A114099(n).

Examples

			a(42) = #{32+5+5, 23+14+5, 14+14+14} = 3.
		

Crossrefs

Cf. A010888.
A147706. [From Reinhard Zumkeller, Nov 11 2008]

A116377 Number of partitions of n into parts with digital root = 7.

Original entry on oeis.org

0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0, 1, 0, 1, 0, 1, 0, 0, 1, 0, 1, 0, 2, 0, 1, 1, 0, 1, 0, 2, 0, 2, 1, 1, 1, 0, 2, 0, 3, 1, 3, 1, 1, 2, 0, 3, 1, 4, 1, 3, 2, 1, 3, 1, 5, 1, 5, 2, 4, 3, 2, 5, 1, 6, 2, 7, 3, 5, 5, 2, 7, 2, 9, 3, 9, 5, 6, 7, 3, 10, 3, 12, 5, 11, 7, 7, 11, 4, 14, 5, 16, 7, 14
Offset: 1

Views

Author

Reinhard Zumkeller, Feb 12 2006

Keywords

Comments

a(n) = A114102(n) - A116371(n) - A116372(n) - A116373(n) - A116374(n) - A116375(n) - A116376(n) - A116378(n) - A114099(n).

Examples

			a(48) = #{34+7+7, 25+16+7, 16+16+16} = 3.
		

Crossrefs

Cf. A010888.
A147706. [From Reinhard Zumkeller, Nov 11 2008]

A116378 Number of partitions of n into parts with digital root = 8.

Original entry on oeis.org

0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0, 0, 0, 1, 1, 1, 0, 0, 0, 0, 0, 1, 1, 2, 1, 0, 0, 0, 0, 1, 1, 2, 2, 1, 0, 0, 0, 1, 1, 2, 3, 3, 1, 0, 0, 1, 1, 2, 3, 4, 3, 1, 0, 1, 1, 2, 3, 5, 5, 4, 1, 1, 1, 2, 3, 5, 6, 7, 4, 2, 1, 2, 3, 5, 7, 9, 8, 6, 2, 2, 3, 5, 7, 10, 11, 11, 6, 3, 3, 5, 7, 11, 13
Offset: 1

Views

Author

Reinhard Zumkeller, Feb 12 2006

Keywords

Comments

a(n) = A114102(n) - A116371(n) - A116372(n) - A116373(n) - A116374(n) - A116375(n) - A116376(n) - A116377(n) - A114099(n).

Examples

			a(51) = #{35+8+8, 26+17+8, 17+17+17} = 3.
		

Crossrefs

Cf. A010888.
A147706. [From Reinhard Zumkeller, Nov 11 2008]
Showing 1-10 of 12 results. Next