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.

Previous Showing 11-20 of 20 results.

A318597 Number of n-member subsets of [9*n] whose elements sum to a multiple of nine.

Original entry on oeis.org

1, 1, 17, 327, 6545, 135751, 2869719, 61474519, 1329890705, 28987537806, 635627275767, 14005614014756, 309847743790935, 6878045467021470, 153121753939078375, 3417374882384868702, 76435265515004093841, 1712879663609111933495, 38450113512250685307822
Offset: 0

Views

Author

Alois P. Heinz, Aug 29 2018

Keywords

Examples

			a(2) = 17: {1,8}, {1,17}, {2,7}, {2,16}, {3,6}, {3,15}, {4,5}, {4,14}, {5,13}, {6,12}, {7,11}, {8,10}, {9,18}, {10,17}, {11,16}, {12,15}, {13,14}.
		

Crossrefs

Column k=9 of A318557.

A318598 Number of n-member subsets of [10*n] whose elements sum to a multiple of ten.

Original entry on oeis.org

1, 1, 18, 406, 9158, 211880, 5005980, 119877472, 2898762854, 70625252863, 1731030733840, 42634215112710, 1054285960975268, 26159486052576800, 650961394904288192, 16239221627803363280, 405994987399334500710, 10169699086799914175514, 255172150241034559336782
Offset: 0

Views

Author

Alois P. Heinz, Aug 29 2018

Keywords

Examples

			a(2) = 18: {1,9}, {1,19}, {2,8}, {2,18}, {3,7}, {3,17}, {4,6}, {4,16}, {5,15}, {6,14}, {7,13}, {8,12}, {9,11}, {10,20}, {11,19}, {12,18}, {13,17}, {14,16}.
		

Crossrefs

Column k=10 of A318557.

A318624 Number of 3-member subsets of [3*n] whose elements sum to a multiple of n.

Original entry on oeis.org

0, 1, 10, 30, 55, 91, 138, 190, 253, 327, 406, 496, 597, 703, 820, 948, 1081, 1225, 1380, 1540, 1711, 1893, 2080, 2278, 2487, 2701, 2926, 3162, 3403, 3655, 3918, 4186, 4465, 4755, 5050, 5356, 5673, 5995, 6328, 6672, 7021, 7381, 7752, 8128, 8515, 8913, 9316
Offset: 0

Views

Author

Alois P. Heinz, Aug 30 2018

Keywords

Examples

			a(1) = 1: {1,2,3}.
a(2) = 10: {1,2,3}, {1,2,5}, {1,3,4}, {1,3,6}, {1,4,5}, {1,5,6}, {2,3,5}, {2,4,6}, {3,4,5}, {3,5,6}.
a(3) = 30: {1,2,3}, {1,2,6}, {1,2,9}, {1,3,5}, {1,3,8}, {1,4,7}, {1,5,6}, {1,5,9}, {1,6,8}, {1,8,9}, {2,3,4}, {2,3,7}, {2,4,6}, {2,4,9}, {2,5,8}, {2,6,7}, {2,7,9}, {3,4,5}, {3,4,8}, {3,5,7}, {3,6,9}, {3,7,8}, {4,5,6}, {4,5,9}, {4,6,8}, {4,8,9}, {5,6,7}, {5,7,9}, {6,7,8}, {7,8,9}.
		

Crossrefs

Row n=3 of A318557.

Programs

  • Mathematica
    LinearRecurrence[{2,-1,1,-2,1},{0,1,10,30,55,91},50] (* Harvey P. Dale, Mar 27 2019 *)

Formula

G.f.: -x*(3*x^4+4*x^3+11*x^2+8*x+1)/((x^2+x+1)*(x-1)^3).
a(n) = 2*a(n-1) -a(n-2) +a(n-3) -2*a(n-4) +a(n-5) for n>5.
3*a(n) = 5+2*A099837(n)+27*n*(n-1)/2 for n>0. - R. J. Mathar, Sep 02 2018

A318625 Number of 4-member subsets of [4*n] whose elements sum to a multiple of n.

Original entry on oeis.org

0, 1, 38, 165, 460, 969, 1782, 2925, 4508, 6545, 9158, 12341, 16236, 20825, 26262, 32509, 39740, 47905, 57190, 67525, 79116, 91881, 106038, 121485, 138460, 156849, 176902, 198485, 221868, 246905, 273878, 302621, 333436, 366145, 401062, 437989, 477260, 518665
Offset: 0

Views

Author

Alois P. Heinz, Aug 30 2018

Keywords

Examples

			a(2) = 38: {1,2,3,4}, {1,2,3,6}, {1,2,3,8}, {1,2,4,5}, {1,2,4,7}, {1,2,5,6}, {1,2,5,8}, {1,2,6,7}, {1,2,7,8}, {1,3,4,6}, {1,3,4,8}, {1,3,5,7}, {1,3,6,8}, {1,4,5,6}, {1,4,5,8}, {1,4,6,7}, {1,4,7,8}, {1,5,6,8}, {1,6,7,8}, {2,3,4,5}, {2,3,4,7}, {2,3,5,6}, {2,3,5,8}, {2,3,6,7}, {2,3,7,8}, {2,4,5,7}, {2,4,6,8}, {2,5,6,7}, {2,5,7,8}, {3,4,5,6}, {3,4,5,8}, {3,4,6,7}, {3,4,7,8}, {3,5,6,8}, {3,6,7,8}, {4,5,6,7}, {4,5,7,8}, {5,6,7,8}.
		

Crossrefs

Row n=4 of A318557.

Formula

G.f.: x*(4*x^7+27*x^6+100*x^5+123*x^4+132*x^3+89*x^2+36*x+1) / ((x^2+1) *(x+1)^2 *(x-1)^4).

A318626 Number of 5-member subsets of [5*n] whose elements sum to a multiple of n.

Original entry on oeis.org

0, 1, 126, 1001, 3876, 10630, 23751, 46376, 82251, 135751, 211880, 316251, 455126, 635376, 864501, 1150630, 1502501, 1929501, 2441626, 3049501, 3764380, 4598126, 5563251, 6672876, 7940751, 9381255, 11009376, 12840751, 14891626, 17178876, 19720005, 22533126
Offset: 0

Views

Author

Alois P. Heinz, Aug 30 2018

Keywords

Crossrefs

Row n=5 of A318557.

Programs

  • Mathematica
    LinearRecurrence[{4,-6,4,-1,1,-4,6,-4,1},{0,1,126,1001,3876,10630,23751,46376,82251,135751},40] (* Harvey P. Dale, Jul 13 2019 *)

Formula

G.f.: -x*(5*x^8+106*x^7+527*x^6+608*x^5+629*x^4+624*x^3+503*x^2+122*x+1) / ((x^4+x^3+x^2+x+1) *(x-1)^5).
a(n) = (-250*n +216/5 + 625*n^4 -1250*n^3 +875*n^2)/24 +4* b(n)/5 for n>=1, where b(n) = b(n-5) = 4, -1, -1, -1, -1, 4, -1, -1, -1,.. 5-periodic for n>=0. - R. J. Mathar, Apr 17 2024

A318627 Number of 6-member subsets of [6*n] whose elements sum to a multiple of n.

Original entry on oeis.org

0, 1, 452, 6198, 33594, 118755, 324516, 749398, 1533686, 2869719, 5005980, 8259888, 13019358, 19757815, 29033576, 41507700, 57939438, 79208745, 106307256, 140364532, 182635562, 234531357, 297600576, 373566942, 464304450, 571880029, 698523980, 846678498
Offset: 0

Views

Author

Alois P. Heinz, Aug 30 2018

Keywords

Crossrefs

Row n=6 of A318557.

Formula

G.f.: x*(6*x^14 +450*x^13 +5286*x^12 +20787*x^11 +46696*x^10 +72381*x^9 +88225*x^8 +92230*x^7 +88135*x^6 +72457*x^5 +46726*x^4 +20749*x^3 +5293*x^2 +450*x+1) / ((x^2-x+1) *(x^2+x+1)^2 *(x+1)^3 *(x-1)^6).

A318628 Number of 7-member subsets of [7*n] whose elements sum to a multiple of n.

Original entry on oeis.org

0, 1, 1716, 38760, 296010, 1344904, 4496388, 12271518, 28989675, 61474519, 119877472, 218618940, 377447148, 622614630, 988172374, 1517381580, 2264243157, 3295144749, 4690625500, 6547258432, 8979650478, 12122560170, 16133132940, 21193254160, 27512019711
Offset: 0

Views

Author

Alois P. Heinz, Aug 30 2018

Keywords

Crossrefs

Row n=7 of A318557.

Formula

G.f.: -x*(7*x^12 +1674*x^11 +28569*x^10 +89050*x^9 +116029*x^8 +117612*x^7 +117655*x^6 +117648*x^5 +115939*x^4 +89170*x^3 +28479*x^2 +1710*x+1) / ((x^6+x^5+x^4+x^3+x^2+x+1) *(x-1)^7).
a(n) = 6*a(n-1) - 15*a(n-2) + 20*a(n-3) - 15*a(n-4) + 6*a(n-5) - a(n-6) + a(n-7) - 6*a(n-8) + 15*a(n-9) - 20*a(n-10) + 15*a(n-11) - 6*a(n-12) + a(n-13). - Wesley Ivan Hurt, Mar 25 2023

A318629 Number of 8-member subsets of [8*n] whose elements sum to a multiple of n.

Original entry on oeis.org

0, 1, 6470, 245157, 2630044, 15380937, 62893270, 202927725, 553275192, 1329890705, 2898762854, 5843355957, 11050100956, 19813501785, 33963673590, 56017460733, 89356455544, 138432467745, 209004466054, 308406729925, 445853163548, 632776453353, 883208213270
Offset: 0

Views

Author

Alois P. Heinz, Aug 30 2018

Keywords

Crossrefs

Row n=8 of A318557.

Formula

G.f.: x*(8*x^19 +6403*x^18 +219614*x^17 +1674059*x^16 +5870564*x^15 +12792670*x^14 +20763588*x^13 +27678950*x^12 +31887236*x^11 +33320524*x^10 +33336672*x^9 +31872212*x^8 +27691884*x^7 +20753602*x^6 +12799164*x^5 +5867258*x^4 +1675300*x^3 +219281*x^2 +6466*x+1) / ((x^4+1) *(x^2+1)^2 *(x+1)^4 *(x-1)^8).

A318630 Number of 9-member subsets of [9*n] whose elements sum to a multiple of n.

Original entry on oeis.org

0, 1, 24310, 1562331, 23535820, 177232627, 886322982, 3381098545, 10639125640, 28987537806, 70625252863, 157366449604, 325949658015, 635299897870, 1176174344125, 2083664997876, 3553074951283, 5859727868575, 9383313282102, 14637413449945, 22304900540890
Offset: 0

Views

Author

Alois P. Heinz, Aug 30 2018

Keywords

Crossrefs

Row n=9 of A318557.

Formula

G.f.: -x*(9*x^20 +24256*x^19 +1416550*x^18 +14526732*x^17 +58916595*x^16 +142251894*x^15 +245168253*x^14 +328503852*x^13 +372895647*x^12 +386000952*x^11 +387373441*x^10 +386005450*x^9 +372890715*x^8 +328505514*x^7 +245169837*x^6 +142249572*x^5 +58917879*x^4 +14526462*x^3 +1416486*x^2 +24304*x+1) / ((x^6+x^3+1) *(x^2+x+1)^3 *(x-1)^9).

A318631 Number of 10-member subsets of [10*n] whose elements sum to a multiple of n.

Original entry on oeis.org

0, 1, 92252, 10015005, 211911256, 2054455670, 12565647510, 56672074888, 205811431514, 635627275767, 1731030733840, 4263421511271, 9672347764772, 20492404684400, 40975640875026, 77970286548270, 142128053955030, 249524848105533, 423793107835284, 698878653009537
Offset: 0

Views

Author

Alois P. Heinz, Aug 30 2018

Keywords

Crossrefs

Row n=10 of A318557.

Formula

G.f.: x*(10*x^26 +92338*x^25 +9646514*x^24 +172035984*x^23 +1227946110*x^22 +4890258085*x^21 +12890246964*x^20 +25218221137*x^19 +40000080160*x^18 +54781619237*x^17 +67109913895*x^16 +75109489209*x^15 +78762565667*x^14 +79655768180*x^13 +78762567575*x^12 +75109489423*x^11 +67109913979*x^10 +54781618619*x^9 +40000079524*x^8 +25218220679*x^7 +12890245939*x^6 +4890259109*x^5 +1227947663*x^4 +172035752*x^3 +9645999*x^2 +92248*x+1) / ((x^4-x^3+x^2-x+1) *(x^4+x^3+x^2+x+1)^2 *(x+1)^5 *(x-1)^10).
Previous Showing 11-20 of 20 results.