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A254956 Zeroless numbers n with digits d_1, d_2, ..., d_k such that d_1*(d_1+1)/2 + ... + d_k*(d_k+1)/2 is a triangular number. 1
1, 2, 3, 4, 5, 6, 7, 8, 9, 22, 35, 49, 53, 56, 65, 69, 94, 96, 111, 123, 132, 136, 144, 163, 199, 213, 225, 231, 233, 238, 245, 252, 254, 266, 283, 312, 316, 321, 323, 328, 332, 355, 359, 361, 367, 376, 382, 388, 395, 414, 425, 441, 452, 477, 489, 498, 522, 524, 535, 539, 542, 553, 555, 558, 585, 593, 599, 613, 626, 631 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,2
COMMENTS
Any one of these terms can have an arbitrary number of 0's in between any two digits. Thus, the numbers with 0's have been omitted as trivial.
LINKS
PROG
(PARI) istri(n)=for(k=0, n+1, if(k*(k+1)/2==n, return(1))); 0
for(n=1, 10^3, d=digits(n); if(vecsort(d, , 8)[1], s=0; for(i=1, #d, s+=d[i]*(d[i]+1)/2); if(istri(s), print1(n, ", "))))
CROSSREFS
Cf. A000217.
Sequence in context: A274126 A108194 A083158 * A061013 A037264 A274124
KEYWORD
nonn,base
AUTHOR
Derek Orr, Feb 11 2015
STATUS
approved

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Last modified April 15 02:01 EDT 2024. Contains 371667 sequences. (Running on oeis4.)