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A371102
Array A read by upward antidiagonals in which the entry A(n,k) in row n and column k is defined by A(1, k) = 4*k-1, and A(n+1, k) = A371094(A(n, k)), n,k >= 1.
8
3, 21, 7, 5461, 45, 11, 357913941, 1109, 69, 15, 1537228672809129301, 873813, 3413, 93, 19, 28356863910078205288614550619314017621, 1466015503701, 22369621, 2261, 117, 23, 9649340769776349618630915417390658987772498722136713669954798667326094136661, 25790417485112089060398421, 6004799503160661, 873813, 11605, 141, 27
OFFSET
1,1
EXAMPLE
Array begins:
n\k| 1 2 3 4 5 6 7
---+--------------------------------------------------------------------
1 | 3, 7, 11, 15, 19, 23, 27,
2 | 21, 45, 69, 93, 117, 141, 165,
3 | 5461, 1109, 3413, 2261, 11605, 3413, 8021,
4 | 357913941, 873813, 22369621, 873813, 72701269, 22369621, 12408149,
PROG
(PARI)
up_to = 105;
A371094(n) = { my(m=1+3*n, e=valuation(m, 2)); ((m*(2^e)) + (((4^e)-1)/3)); };
A371102sq(n, k) = if(1==n, 4*k-1, A371094(A371102sq(n-1, k)));
A371102list(up_to) = { my(v = vector(up_to), i=0); for(a=1, oo, for(col=1, a, i++; if(i > up_to, return(v)); v[i] = A371102sq((a-(col-1)), col))); (v); };
v371102 = A371102list(up_to);
A371102(n) = v371102[n];
CROSSREFS
Cf. A004767 (row 1), A102603 (row 2), A371094.
Cf. also arrays A257852, A371096, A371100, A371103.
Sequence in context: A361153 A229197 A188721 * A367324 A212996 A089999
KEYWORD
nonn,tabl,easy
AUTHOR
Antti Karttunen, Apr 21 2024
STATUS
approved