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A373172 a(1) = 1; for n >= 2, a(n) = noz(a(n-1) + 4*n - 3), where noz(n) = A004719(n).

%I A373172 #17 Jul 08 2024 13:18:12
%S A373172 1,6,15,28,45,66,91,12,45,82,123,168,217,27,84,145,21,9,82,159,24,19,
%T A373172 18,111,28,129,234,343,456,573,694,819,948,181,318,459,64,213,366,523,
%U A373172 684,849,118,291,468,649,834,123,316,513,714,919,1128,1341,1558,1779
%N A373172 a(1) = 1; for n >= 2, a(n) = noz(a(n-1) + 4*n - 3), where noz(n) = A004719(n).
%C A373172 Zeroless analog of the positive hexagonal numbers.
%H A373172 Paolo Xausa, <a href="/A373172/b373172.txt">Table of n, a(n) for n = 1..10000</a>
%t A373172 noz[n_] := FromDigits[DeleteCases[IntegerDigits[n], 0]];
%t A373172 Block[{n = 1}, NestList[noz[++n*4 - 3 + #] &, 1, 100]]
%t A373172 nxt[{n_,a_}]:={n+1,FromDigits[DeleteCases[IntegerDigits[a+4n+1],0]]}; NestList[nxt,{1,1},60][[;;,2]] (* _Harvey P. Dale_, Jul 08 2024 *)
%o A373172 (PARI) noz(n) = fromdigits(select(sign, digits(n))); \\ A004719
%o A373172 lista(nn) = my(va=vector(nn)); for (n=1, nn, va[n] = if (n==1, 1, noz(va[n-1] + 4*n - 3))); va; \\ _Michel Marcus_, Jun 03 2024
%Y A373172 Row n = 6 of A373169.
%Y A373172 Cf. A000384, A004719, A243658, A370812, A373171.
%K A373172 nonn,base,easy
%O A373172 1,2
%A A373172 _Paolo Xausa_, May 28 2024